# pvc overflow



## beaslbob (May 29, 2009)

Just played around with the gallery

here is my schematic of a pvc overflow.

FWIW and FYI






Aquarium Gallery - flatdetailedsurfaceskimmer


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## phil_pl (Apr 10, 2009)

looks like a great idea i would go with the surface skimming version myself


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## beaslbob (May 29, 2009)

Thanks

If anyone is interested in actually building this please keep in mind that it is a schematic. So please play around with it to get something more useful.

What I did was setup a 10g tank and a couple of plastic tubs as a test setup. You could just use tubs also but I had an "extra" 10g around.

One thing with this particular design is that I found it hard to mount it on the tank. It is unbalanced and some type of "hanger" was required to keep the overflow section in place on the tank.

I did could up with a couple of designs were I used two in tank hob siphons. That was balanced and much easier to mount to the tank. With those it hob siphons formed a balanced hanger so you just place it on the tank.

If anyone runs off and builds this please feel free to contact me at [email protected] or this thread.

One of the comments I get sometimes I how does this thing possibly work. It does.

my .02


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## SteelGluer (Nov 7, 2008)

Try this


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## aspects (Feb 22, 2009)

hey i know that pic 










also, heres an explaination for those who might no be clear on its function (its a slideshow. lol.)










and a link to one a member here built 

http://www.aquariumforum.com/f34/diy-wet-dry-trickle-filter-4211.html


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## BigandUgly (Sep 24, 2009)

Instea of adding the big uptube, couldn't you just drill a few small holes where you'd want the lowest level of water to be? If the water level fell below that point due to power outage the siphon would stop.


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## aspects (Feb 22, 2009)

that would drain the entire system on shut down, and the overflow would lose its prime.
in the case of a short power outage, this means when the power comes back on, the overflow will not be functional, and all the water from your sump would flow into the tank, and on to your floor


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## beaslbob (May 29, 2009)

SteelGluer said:


> Try this



Reference the picture posted above.

"my" design I have "F" much higher where the middle of the horizontal part determines the tank level. So the overflow is actually internal to the pvc and external to the tank.

I have never tested the design posted but my "gut feel" is there is not enough water "trapped" in the pvc to keep it primed in a power outage. So it will restart reliably on power return.

But then people use that design and swear by it.

So perhaps I am missing something.

my .02


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## drhank (Aug 3, 2009)

You might want to add a strainer on the tank side. It might help keep fish out of the sump.


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## BigandUgly (Sep 24, 2009)

drhank said:


> You might want to add a strainer on the tank side. It might help keep fish out of the sump.


But they might like riding the new waterslide...


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## SteelGluer (Nov 7, 2008)

beaslbob said:


> Reference the picture posted above.
> 
> "my" design I have "F" much higher where the middle of the horizontal part determines the tank level. So the overflow is actually internal to the pvc and external to the tank.
> 
> ...


I have had this on my reef tank for 4 years now my sump is in the basement nomatter if power goes out it starts right back up never once had a proble with it losing siphon.


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## beaslbob (May 29, 2009)

SteelGluer said:


> I have had this on my reef tank for 4 years now my sump is in the basement nomatter if power goes out it starts right back up never once had a proble with it losing siphon.



I am curious. When there is a power out does the water stay in the external riser above "F" or does that riser drain down to "F". And does the over the tank part remain full of water?


I have never tested that design so am curious.

my .02


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## aspects (Feb 22, 2009)

beaslbob said:


> I am curious. When there is a power out does the water stay in the external riser above "F" or does that riser drain down to "F". And does the over the tank part remain full of water?
> 
> 
> I have never tested that design so am curious.
> ...



again, please reference this .gif


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## beaslbob (May 29, 2009)

aspects said:


> again, please reference this .gif



Will have to from home computer. Can't see photobucket stuff at work.

Thanks for posting


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## aspects (Feb 22, 2009)

I see. 
Well whenever you get a chance, check it out. It explains the entire function of a PVC overflow. 
But to answer your question, yes, the to loop stays filled, and the two bottom loops drain to below the "T" fitting in the back of the overflow. When power returns, the first loop fills with water, and the overflow resumes function.


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## aspects (Feb 22, 2009)

Hopefully this works. Never tried adding attachments from my phone before.


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## beaslbob (May 29, 2009)

aspects said:


> Hopefully this works. Never tried adding attachments from my phone before.



Your posting worked beautifully. And confirmed the way I thought it would work.

My concern is that proper operation as shown is dependant upon the over the glass never never accumulating air and remaining full of water. 

But during power out (or even normal operation) air could accumulate just above the glass and break the siphon in the over the glass part.

In that case the over the top would drain to the level of the horizontal part of "F". And there is not enough water trapped below "F" to restart the siphon on power resume. There must be enough water trapped to fill the siphon tube when the air is sucked out of the siphon tube. Otherwise you would start sucking air from above "F" before the siphon is reformed.

With the design I posted above there is enough water traped to restart the siphon. And I use a powerhead to suck the air out of over the tank siphon. Which I have tested numerous times even adding air in the over the glass part and breaking the siphon. In each case the return pump fills the tank, starts sucking air (a necessary adjustment in sumps), the powerhead venturi sucks out the air in the pvc. Siphon restarts. The sump fills. and the return pump returns to pumping water.

This works even if the powerhead/return pump venturi is very slow at sucking out the air from the over the glass pvc. Then in normal operation air bubbles entering the drain are removed from the over the glass part as part of normal operation. Further insuring air is removed from that pipe. I tested that by putting an air pump output directly in the in tank drain and the siphon continued with air bubbles being removed by the pumps.




But siphon breaks in "your" design must not happen too often as people have used that design for some time. 







but with occasional restart complaints.



Thanks for posting.

my .02


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## aspects (Feb 22, 2009)

Generally cavitation is not a problem if set up properly. Also, this is the reason for the check valve added to the top.
By drilling a small hole in the top and gluing in an inline check valve, you give any excess air a place to escape to. The waterpressure in the pipes will help push out excess air.
Also, there is a product called an "aqualifter". This can also be connected to the check valve, and will constantly pull out any air in the system. Its a bit overkill, but failsafe. 

What I did was connect a long airline to the checkvalve, and run the other end to the venturi of a powerhead. It serves the same purpose as the "aqualifter". But these things are really only needed if you don't properly size your pump to your overflow. I am running a low flow trickle system, so the risk of cavitation is much higher than if I were running a properly sized pump (400gph w/ a 3/4" overflow)


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## beaslbob (May 29, 2009)

And actually the only real difference between the two designs is the height of "F". 

Interesting using the check valve. 

And I so use a venturi on a powerhead also. Without a check valve. With water a small amount of water is just recirculated back to the tank is all.


But then I guess pwerheads, aqualifters, check valves can all fail at some point.


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## aspects (Feb 22, 2009)

Theoretically, the higher you place the "T" the more pressure you will need to restart the overflow. If there is not enough pressure, the rather might fill the display before the overflow catches up. (not positive on this. One, but I will. Ask)

If built properly, the chance of something failing are slim. Thou, you are right, there is always a chance, however small it may be. This is why drilling the tank is really the only failsafe method. Though even then, if your overflow bulkhead clogs, or the piping clogs, you still run that slight risk. I guess its just a matt what you're comfortable with. I know people who have been running their PVC overflows for many years with no problems, and I have yet to run into any problems after initial set up. But other people may not be willing to chance it.


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## beaslbob (May 29, 2009)

aspects said:


> Theoretically, the higher you place the "T" the more pressure you will need to restart the overflow. If there is not enough pressure, the rather might fill the display before the overflow catches up. (not positive on this. One, but I will. Ask)


Actually I think you got it turned around. First there must be enough water in the water trap to fill the over the glass and restart the siphon. Secondly, The higher the water is up in the water trap the less vacume is required suck that water up to reestablish the siphon. Inside the tank can be either the loop you have or just a single pipe. As long as the single pipe remains underwater the tank side can reestablish the siphon with the vacume. But with that system the power our level is determined by the vertical location of "F". So that has to be much higher then the design you posted. That design uses the inner loop to determine the power out water level. And that can be used even with "F" much higher.

As I stated the main design difference is simply the location of "F"



> If built properly, the chance of something failing are slim. Thou, you are right, there is always a chance, however small it may be. This is why drilling the tank is really the only failsafe method. Though even then, if your overflow bulkhead clogs, or the piping clogs, you still run that slight risk. I guess its just a matt what you're comfortable with. I know people who have been running their PVC overflows for many years with no problems, and I have yet to run into any problems after initial set up. But other people may not be willing to chance it.


Or you crack the tank. Or the bulkhead leaks. etc etc etc.

the best you can do is to design and test it as much as possible.

power out to see of the sump floods.

power restart to see if normal operation returns.

failed overflow (siphon, blackage, etc etc) see if the display floods.

I have found out that there is usually a very narrow range where all those are met. Adding an automatic top off can screw that up also as water is added when the sump lowers. Which is fine for evaporation but can flood the display if it is from overflow failure. So I recommend some kind of drip system. Which can be a bear to adjust.

Have really enjoyed. Very enlightening. Thanks


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## beaslbob (May 29, 2009)

And here is a picture of my first test unit. If you study it closley you will notice that "F" from before is much higher and the riser tube is just shorter. And I also show the drain to the sump and don't use the inside loop surface skimmer.

this picture is a mag 7 pumping against a 4' head.










Hidden behind the hob part is the in tank drain which is just a straight pvc pipe going down about 2/3 the way into the tank.


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## SteelGluer (Nov 7, 2008)

beaslbob said:


> I am curious. When there is a power out does the water stay in the external riser above "F" or does that riser drain down to "F". And does the over the tank part remain full of water?
> 
> 
> I have never tested that design so am curious.
> ...


Th e water will stop at B will not go over D next to F


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## beaslbob (May 29, 2009)

SteelGluer said:


> Th e water will stop at B will not go over D next to F


Got that.

under power out it would seem the outside the tank part would drain down to "F". And if the over the tank part has no air leaks then it stays primed. So normal operation would return on power resume.

but if air does accumulate or if "G" has an air leak then the over the tank part breaks siphon. The in tank loop is at the top of "B" but the external loop is down to "F". So to restart the siphon the water in the external trap at "F" must be sucked up the pvc pipe. My fear is that there is not enough water trapped to restart the siphon.

In order to insure there is enough water traped to restart the siphon you could just raise the position of "F" to just below the top of "B". That way "F" traps much more water at a higher level. Helping insure the siphon is restarted.

To exaggerate my point consider placing the "F" near a sump in the basement. Say 15' below the tank. There would be a much greater cavitation potential. Greater check valve/aqua lifter failure. And not enough water trapped to reestablish the siphon. All of which is avoided by raising "F" to just below the top of "B"

just my .02


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## SteelGluer (Nov 7, 2008)

beaslbob said:


> Got that.
> 
> under power out it would seem the outside the tank part would drain down to "F". And if the over the tank part has no air leaks then it stays primed. So normal operation would return on power resume.
> 
> ...


There is no reason to do anything to this. The instructions I posted for it works 100%. You know what they say if its not broke Dont fix it.
Remember what I said it been on my reef tank for 4 years. Hasn't lost siphon once in that time.

There is no reason to do anything to this. The instructions I posted for it works 100%. You know what they say if its not broke Dont fix it.


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## beaslbob (May 29, 2009)

Thank you very much

It has been an interesting discussion.



my .02


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## aspects (Feb 22, 2009)

Have you has a chance to do a shut down/ start up test on your design yet? I'm interested to see the outcome. 
I haven't had a chance to pass the design along yet, but I will try to consult some peopl about it when I get home from work. 
If you can, PM me the design drawing (w/o the AF logo if possible)


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## beaslbob (May 29, 2009)

aspects said:


> Have you has a chance to do a shut down/ start up test on your design yet? I'm interested to see the outcome.
> I haven't had a chance to pass the design along yet, but I will try to consult some peopl about it when I get home from work.
> If you can, PM me the design drawing (w/o the AF logo if possible)


Hopefully you meant me. Yes I could pass along some pictures and drawings.

Not only have I tested this out but actually did a demo for the a local club meeting. In that demo I started out with filling the sump, showing how the return pump could remotely fill that tank, establishing the siphon, and adjusting the system to prevent flooding.

In the testing and demo's I plug the overflow as well as remove the suction lines on the over the tank part to allow air to enter and break siphon. I also demo the air pump pumping air into the drain to show the venturi suction lines sucking the air out. 

And of course the normal power out power return conditions.

I am at work now but will try pming/emailing pictures/drawings at home tonight.


my .02


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## aspects (Feb 22, 2009)

Very nice! Looks like you got all the test taken care of. That's awesome.


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## beaslbob (May 29, 2009)

aspects said:


> Have you has a chance to do a shut down/ start up test on your design yet? I'm interested to see the outcome.
> I haven't had a chance to pass the design along yet, but I will try to consult some peopl about it when I get home from work.
> If you can, PM me the design drawing (w/o the AF logo if possible)


Here is a link to my photobucket page. It has the above plus a revb (in album refb LOL) and a rev c which is similiar to the drawing I started this thread with. Only in these pictures I used straight tees instead of the curved sanitary tees which I now recommend.

Click on those albumns to see those designs.

also is a test setup in my messy garadge

pvcoverflow pictures by beaslebob - Photobucket


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## rynox77 (Aug 11, 2009)

Beautiful. I've been pricing overflow boxes and for the price of a good overflow, you could easily build two of these contraptions to work in tandem and should fail over if one doesn't start properly after power fail.


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## aspects (Feb 22, 2009)

Actually. Given the price of PVC, you could easily make quite a few overflows. 10' lengths of PVC only cost a couple of dollars. (I believe 10' @ 1" is around $3)


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## rynox77 (Aug 11, 2009)

Exactly. I've nearly worked up the bravery to build my own sump & refugium. If some PVC and strainer will replace an $80 part It would certainly help my case. I'm going to pick up some 1/2" PVC on my way home from work and experiment tonight with a bucket.

The thing is I don't want to drill my aquarium and I don't want a wet floor.


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## aspects (Feb 22, 2009)

For what size tank? 
1/2" is too small for most applications.


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## beaslbob (May 29, 2009)

I even tried (without any success) to heat up pvc filled with sand to form an p or s trap. Found it easier to just buy the elbows and tee's.

Let us know how your testing works. 

Perhaps you can come up with a rev d to "my" design. 


FWIW the sanitary tee's in my drawing could be replaced with just regular tee's for testing.

Also 1/2" will probably not allow much flow. But it will be nice and quiet as the pipe will be full of water. Larger diameters do allow more flow. But unless the overflow is fairly near it's maximum flow rate there will be some air in the pipe which will cause a small smount of "flow" sound as the over water hits an elbow on it's way to the sump.

I also used a 10g for my tank. You might want to get a couple of plastic storage containers to simulate a sump and tank.



my .02


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## beaslbob (May 29, 2009)

aspects said:


> For what size tank?
> 1/2" is too small for most applications.


Yea but you can buy contractor packs of elbows (and maybe even tees) at 10 for $2 here. sounds like a good plan to just test it out and see if it works.

but I do agree that an over flow with two 1" hob siphon parts would be more useful. In my last testing I used 1" (or1/4") hob parts (2 of them) to a center 2" up then down part. The two overflows were much easier to mount on the tank. It also easily drained a mag 7 pump pumping against a 4" head.


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## rynox77 (Aug 11, 2009)

aspects said:


> For what size tank?
> 1/2" is too small for most applications.


What tank size? This will be a 5 gallon bucket of water draining into a sink. I have no intention of using this for an aquarium, but only a proof-of-concept. I purchased all the stuff for under $5.

If anything really awesome happens, like I actually get it to work, I'll make a video and put it on youtube.

I'll even try to get video of my wife giving me that "what the hell are you doing?" look.


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## rynox77 (Aug 11, 2009)

The first try, I just used 6 elbows, no Ts, no pvc cement, just plugged everything in and it worked.

Will go back in about 30 minutes and pour more water in my bucket to see if the siphon held. It wouldn't surprising me if I have an air leak, though, having not even cemented the pvc.

It's crude at this point, but it works.


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## beaslbob (May 29, 2009)

rynox77 said:


> The first try, I just used 6 elbows, no Ts, no pvc cement, just plugged everything in and it worked.
> 
> Will go back in about 30 minutes and pour more water in my bucket to see if the siphon held. It wouldn't surprising me if I have an air leak, though, having not even cemented the pvc.
> 
> It's crude at this point, but it works.


Excellent. got pictures?

FWIW I set up my first pvc overflow and it worked just fine. Of course that was after 1 year or two of running a sump with the standard dual box overflow.

I showed it to my wife and she was so impressed that she said I should patent it. So I checked and the s (or p) trap was first patented in 1850 or so. *r2

Look at your toilet bowl from the side. You will see why you can slowly pour water in the bowl and the level in the bowl reamains relatively constant as the water goes down the drain. So basically you are turning you tank into a toilet bowl. *o2

my .02


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## beaslbob (May 29, 2009)

Oh yea. Did you have problems first "priming" the siphon and water trap?


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## rynox77 (Aug 11, 2009)

beaslbob said:


> Oh yea. Did you have problems first "priming" the siphon and water trap?


For the record, I also made linguine carbonara last night... it was delicious. I do happen to have a picture of my dinner, but I'm sure you aren't interested in that. Anyways, more to the point, I went back after making dinner and eating, it was probably about an hour or more and it was still working, the prime wasn't lost. That was very surprising to me considering the lack of pvc cement. I thought surely I must have an air leak, but I used pressure fittings that slid in real snug, so I guess it held.

To prime it, I turned the entire unit upside down and filled one end with water until water (with no bubbles) came out the other end. I then held my thumb over the openings and put it in the bucket really quick. Clearly this method of priming wouldn't work in practice, but worked enough to prove the design of the overflow.

The disappointing part, and this is probably due to my shoddy, 2-minute job throwing it together is that the water didn't come out at a full flow, as if it wasn't using the whole 1/2" plumbing. It was more than a trickle, but definitely didn't drain quickly. This is why I ended up not making a video. It was rather anticlimactic.


I do have a question though:


How far down does your plumbing go into your sump? Below water level? If so, isn't it possible the entire drainage plumbing could fill with water and end up siphoning your entire aquarium into your sump during power off conditions?


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## beaslbob (May 29, 2009)

rynox77 said:


> For the record, I also made linguine carbonara last night... it was delicious. I do happen to have a picture of my dinner, but I'm sure you aren't interested in that. Anyways, more to the point, I went back after making dinner and eating, it was probably about an hour or more and it was still working, the prime wasn't lost. That was very surprising to me considering the lack of pvc cement. I thought surely I must have an air leak, but I used pressure fittings that slid in real snug, so I guess it held.
> 
> To prime it, I turned the entire unit upside down and filled one end with water until water (with no bubbles) came out the other end. I then held my thumb over the openings and put it in the bucket really quick. Clearly this method of priming wouldn't work in practice, but worked enough to prove the design of the overflow.
> 
> ...



Perhaps you have to air bubles at the siphon elbow. That effectively reduces the area for water and limits the flow.

If the entire thing is sealed then the tank water will flow down to the end of the tube in the tank. That tube should be well below where the water stops flowing under power out.

The key is where the sanitary traps are in my first picture. The tops are open to the air (through the priming nipples). That way the water height in the aquarium is determined by the height of the sanitary traps as shown. Water rises to that height then starts flowing down the drain. Then under power out the water flows to the bottom the of sanitary traps then stops. With water "trapped" in the water trap and hob siphons prior to those tees. Then when power resumes there is water in the siphon and water traps so the level rises until it "overflows" in the sanitary tees and normal operation resumes.

If you used elbows for the sanitary tees you could simulate "my" operation by drilling holes at the top of those elbows.

my .02


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## beaslbob (May 29, 2009)

gee

Can I come over for dinner. *pc


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## rynox77 (Aug 11, 2009)

beaslbob said:


> Perhaps you have to air bubles at the siphon elbow. That effectively reduces the area for water and limits the flow.


Very likely.




beaslbob said:


> The key is where the sanitary traps are in my first picture. The tops are open to the air (through the priming nipples). That way the water height in the aquarium is determined by the height of the sanitary traps as shown.


Ohhh, the light bulb just went on. Got it. *i/d*




beaslbob said:


> gee
> 
> Can I come over for dinner. *pc


lol


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## beaslbob (May 29, 2009)

rynox77 said:


> ...
> 
> 
> Ohhh, the light bulb just went on. Got it. *i/d*
> ...


now you're really on the right track.!!!!!*Glasses*


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## aspects (Feb 22, 2009)

lol. i just realized that your design is the same as my bottom siphon overflow, just without the extension inside the tank. 

cant you get T's and elbows in a 1" pack? here they have them from 1/2"-2" in the contractor packs


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## rynox77 (Aug 11, 2009)

I used Ts instead of joints and left them open to the air and I actual had much better water flow than using 6 elbows. Here's the video.








Obviously, I'll have to use 1" plumbing and tweak the dimensions, but the point is proven.


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## aspects (Feb 22, 2009)

what point? i think i missed that part


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## rynox77 (Aug 11, 2009)

aspects said:


> what point? i think i missed that part


I proved that this device that aquarists have been using for years actually works. You're welcome.

More importantly, I satisfied my own curiosity. I would trust a self-made pvc overflow far more than I would a box overflow purchased from Amazon.


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## beaslbob (May 29, 2009)

rynox77 said:


> I used Ts instead of joints and left them open to the air and I actual had much better water flow than using 6 elbows. Here's the video.
> ....
> 
> Obviously, I'll have to use 1" plumbing and tweak the dimensions, but the point is proven.


I found more water flow also when the outside Tees were open to the air also.

Amazing what a few bucks of pvc can do. 

Congrates. sounds like your experiment worked very well. 

FWIW I have had some people attempt to build these things with no success because they did not fully understand and/or implement the design. Fortunately you got it working. So either you're a good designer or listener or both. *w3


my .02


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## Freemind (May 16, 2010)

Whoever designed this overflow is a genius!!!

*THANK YOU!!!* Works *great*!!!!!!!!


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## beaslbob (May 29, 2009)

Freemind said:


> Whoever designed this overflow is a genius!!!
> 
> *THANK YOU!!!* Works *great*!!!!!!!!


Good glad it worked and thanks for the feedback.

actually I did design with my own thoughts the design I presented.

As far as being a genius I'll let you decide.

I checked and the first patent for an "s" trap (which is what this is) was over 100 years ago. *r2

So much for original thinking. Someone else always beats me to it.

my .02


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## fishrule (May 16, 2010)

This is a really cool design. I just purchased an aqualifter and just for the simplicity of it I am going to go with a CPR overflow. I really like this rendering though. If I do another tank I will definitely make my own overflow.


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## beaslbob (May 29, 2009)

fishrule said:


> This is a really cool design. I just purchased an aqualifter and just for the simplicity of it I am going to go with a CPR overflow. I really like this rendering though. If I do another tank I will definitely make my own overflow.


To serve the aqua lifter function I just used a powerhead with an air line to the top of the HOB part. With a venturi to suck some air/water from the siphon to the powerhead.

To test I put an air pump output under the in tank drain. bubbles were sucked to the power haed away from the sihpon. It also sucks out air to get it going initially.


my .02


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## mtc2010 (Jul 10, 2010)

did you design that in 'paint'?


mtc
http://www.airheatnt.com


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## beaslbob (May 29, 2009)

mtc2010 said:


> did you design that in 'paint'?
> 
> 
> mtc
> http://www.airheatnt.com


My drawing in the first post is with cadopia which functions in much the same manner as autocad.

But then you might have meant the drawing posted by others later.


my .02


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## cocovi (Nov 22, 2010)

The overflow will not be functional .

victory motorcars | lop Seo khoa 2 | lớp Seo khóa 2


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## beaslbob (May 29, 2009)

cocovi said:


> The overflow will not be functional .


Oh why so? seems to work for me anyway.*old dude


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## zio tonino (Feb 21, 2011)

Hi guys 

My name is Tonino and I'm from Italy 

I built an overflow like beaslbob project; but now I have a question for you: I will use it in a freshwater aquarium with many plants and the problem is that after a while of hours of working the inside of tubes will be colonized from algae, microorganisms and dirty particles so I'm thinking at this issue: the suction tube to start the overflow, that is linked to a venturi pump, could be blocked!
So how do you have solved this issue? 
I thought that I can use a larger tube or a T link instead of 90° and use the "tower" of T to suck-out air from siphon.

What do you think about these solutions?


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## beaslbob (May 29, 2009)

zio tonino said:


> Hi guys
> 
> My name is Tonino and I'm from Italy
> 
> ...


Yes you have hit on a maintenance problem. I do not think using a larger tube is the answer. Obviously the tube is for the initial startup and after that just to suck out occasional air bubles. I have ran a u tube On my 55g marine with no venturi and did have to manually suck out the air once a week or so.

thanks for your feedback and to share my experience, I did have to occasionally run a toothpick to clear up the salt accumulation. So I think you will have to do occasional cleaning. But any water going through the venturi is bypassing the overflow so that should be as small as possible.

my .02


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## zio tonino (Feb 21, 2011)

Hi 

I think a solution similar to this










you can see the "tower" on the left and on the right.

the cap has a thread and is screwed so you can open and inspect the inside of the tube; moreover on the cap there is a no return valve.

I think this could be a good idea.

Just a question for you: I saw that all american diy overflow pipe are made with white pvc; here in Italy I found only gray pvc. 
what kind of pvc do you use?:fish-in-a-bag:

bye


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## beaslbob (May 29, 2009)

zio tonino said:


> Hi
> 
> I think a solution similar to this
> 
> ...


Looks like that would work.

The removing the cap will allow the functions I used with the Purple nillple labeled "primer" on the original drawing.

Some have used grey pvc here so that should work as well.

Depending on space I would "flatten" it out so the drain is flat against the aquarium glass. That way there will be less twisting on the tank top and back glass.

But I think you have a workable system.


my .02


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## Machine1515 (Apr 18, 2011)

This system that is depicted in the animation works awesome BUT...I have a flow rate issue. Tables show that my Eheim 1250 is flowing about 165gph at 4' of head and it is way more water then the down pipe can handle. 
I made my down pipe with 1 1/2" I.D. PVC.

I figure there are 3 ways to solve this issue:
1) Get a smaller pump with less flow rate
2) Make a second down pipe system or make another one with a larger I.D.
3) put a dimmer switch for a light fixture in-line with the pump power to slow down the impeller.

I am thinking option 3 will be the cheapest and will allow me to 'dial-in' the flow rate. There is no need for me to cycle my 55 gallon tank 3 times in an hour.
Any thoughts?


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## beaslbob (May 29, 2009)

Machine1515 said:


> This system that is depicted in the animation works awesome BUT...I have a flow rate issue. Tables show that my Eheim 1250 is flowing about 165gph at 4' of head and it is way more water then the down pipe can handle.
> I made my down pipe with 1 1/2" I.D. PVC.
> 
> I figure there are 3 ways to solve this issue:
> ...


1 1/2 pvc should have no problem handling that flow rate.

I say build it and test it out. *old dude

my .02


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## Machine1515 (Apr 18, 2011)

On second thought...Changing the speed of the pump would drastically affect its efficiency. Maybe diverting some of the flow is the answer?


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## beaslbob (May 29, 2009)

Machine1515 said:


> On second thought...Changing the speed of the pump would drastically affect its efficiency. Maybe diverting some of the flow is the answer?


as I remember HOB overflow boxes with 1" diameter U tubes are rated over 600 gallons/hour.

So as I said just build it. It should work just fine.*old dude

my .02


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## wimpyreef (May 15, 2011)

aspects said:


> that would drain the entire system on shut down, and the overflow would lose its prime.
> in the case of a short power outage, this means when the power comes back on, the overflow will not be functional, and all the water from your sump would flow into the tank, and on to your floor


would be a disaster I wouldn't want to come home to.

I Looked into non-drilled overflows using a configuration of pipes, and all i came back with was to get ma dam tank drilled!

Its seems a hell of a lot easier?..no?

But to my defense...all i did was google and youtube for a few mins until i got the "cave man look" like huh???

Which method do ya'll think is better or prefer - drilled or over the tank siphoning?

Is it worth the trouble really?


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## beaslbob (May 29, 2009)

wimpyreef said:


> would be a disaster I wouldn't want to come home to.
> 
> I Looked into non-drilled overflows using a configuration of pipes, and all i came back with was to get ma dam tank drilled!
> 
> ...


Way late on this but drilling existing tanks especially the bottom glass is extremely dangerous. Because it is probably tempered and will shatter. 

I have hear some tank side glass is not tempered and can be drilled.

Either way I would recommend the hang on syphon designs here.

If your tank is already drilled it might be better looking to use the existing holes. Plus some like eliminating the possibility of breaking siphon.

On the other hand using power head(s) to suck out air in the HOB part prevents the siphon loss. Plus the hob overflow can be easily taken off the tank for inspection and cleaning.

my .02


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