# Converting 20g into saltwater



## NursePlaty (Feb 5, 2010)

*I am going to change my 20g L into a saltwater FOWLR tank.
Im new to SW and I forgot to save the help I had gotten before. 
Anyhow I have a couple of questions. 

1. People buy liverock to grow the beneficial bacteria. Cant the beneficial bacteria grow automatically like it does in freshwater? Such as along walls, decorations and etc? Or does it have to be manually introduced. 

2. Does it matter what substrate is used? 50% white sand and 50% crushed coral work? Is this where live sand comes into play? I saw petsmart selling live sand in a bag, wouldnt the organisms already be dead in the bag?

3. If I decide to grow corals, is actinic light needed? I hear it helps with photosynthesis but it is not needed. Will 6500K lights only work? And also how many watts per gallon is needed for with or without coral. I am used to freshwater needing 2-3 watts per gallon to grow plants, and dont know if it is any different with SW. 

4. I heard there's many colors of Coraline algae. I want as many colors as possible, where do I get this? Petsmart and Petco sell them?

5. I am keeping a 20g Long so I am interested in small fish such as clowns, gobys and wrasses. Any restrictions?*


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## LPUIG73 (Jul 18, 2010)

NursePlaty said:


> *I am going to change my 20g L into a saltwater FOWLR tank.
> Im new to SW and I forgot to save the help I had gotten before.
> 
> 5. I am keeping a 20g Long so I am interested in small fish such as clowns, gobys and wrasses. Any restrictions?*


Does this mean you are converting that nice planted freshwater tank of yours? But it looks so nice!

When I began in the hobby, an old friend told me never try saltwater in anything smaller than 30 gallons. Saltwater doesn't carry nearly as much oxygen as freshwater and therefore you'll be very limited in the number & size of saltwater fish you'll be able to stock in 20 gallons.


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## tinman (Nov 3, 2009)

no answers for this long ? 

is it like we have no salt water enthus here ??  

im thinking of buying a 20 long for saltwater corals, so i have same questions


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## Danmaku17 (Jan 3, 2011)

I found on my 29 gallon that its tough to have a small tank for saltwater. It seemed my salt concentration would fluctuate on a dime. Become very annoying having to check on it everyday.


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## FkeidcDmn (Feb 3, 2011)

Danmaku17 said:


> I found on my 29 gallon that its tough to have a small tank for saltwater. It seemed my salt concentration would fluctuate on a dime. Become very annoying having to check on it everyday.


Quick Question: How do you check the salinity of the water? I've seen someone use a meter that tells you the specific gravity of the water, but are there other ways? Like an electronic sensor?


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## Danmaku17 (Jan 3, 2011)

There are probably better ones out there but the basic ones that use gravity and find the salt concentration work perfectly.


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## trouble93 (Nov 8, 2008)

FkeidcDmn said:


> Quick Question: How do you check the salinity of the water? I've seen someone use a meter that tells you the specific gravity of the water, but are there other ways? Like an electronic sensor?


Vertex Salinity Refractometer with ATC - AquaCave
Doesn't have to be this model but the cost is about the same.


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## trouble93 (Nov 8, 2008)

NursePlaty said:


> *I am going to change my 20g L into a saltwater FOWLR tank.
> Im new to SW and I forgot to save the help I had gotten before.
> Anyhow I have a couple of questions.
> 
> ...


 I would post this in the nano reef section. Main reason such a small water volume is hard to keep in check. Water levels can go side ways in a blink of an eye. Me personally I wouldn't do anything smaller then a 55gal. tank. Not to discourage but my first tank was a standard 20gal. Two things can come out of starting with a small tank, you will ether throw it in the back yard and walk away or you will become a pro real fast. For me in a small tank it seemed like I was always casing something. And sorry nobody got to your post sooner.


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## FkeidcDmn (Feb 3, 2011)

Danmaku17 said:


> I found on my 29 gallon that its tough to have a small tank for saltwater. It seemed my salt concentration would fluctuate on a dime. Become very annoying having to check on it everyday.



It's frequently stated that small saltwater tanks have a tendency to have rapidly fluctuating conditions. This includes the salt concentration, apparently.

My question is, what's causing the fluctuation in salinity? I'm surprised the salinity of the water is so unstable in a small tank. Is it the evaporating water?


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## trouble93 (Nov 8, 2008)

FkeidcDmn said:


> It's frequently stated that small saltwater tanks have a tendency to have rapidly fluctuating conditions. This includes the salt concentration, apparently.
> 
> My question is, what's causing the fluctuation in salinity? I'm surprised the salinity of the water is so unstable in a small tank. Is it the evaporating water?


Yes evaporation is the main factor.


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## beaslbob (May 29, 2009)

NursePlaty said:


> *I am going to change my 20g L into a saltwater FOWLR tank.
> Im new to SW and I forgot to save the help I had gotten before.
> Anyhow I have a couple of questions.
> 
> 1. People buy liverock to grow the beneficial bacteria. Cant the beneficial bacteria grow automatically like it does in freshwater? Such as along walls, decorations and etc? Or does it have to be manually introduced. *


*Yes the bacteria does grow automatically, the idea of live rock is to introduce those bacteria. Some claim the anaerobic bacteria control nitrAtes as well. I claim the algae on the rocks is the main benefit. Just like planted FW tanks



2. Does it matter what substrate is used? 50% white sand and 50% crushed coral work? Is this where live sand comes into play? I saw petsmart selling live sand in a bag, wouldnt the organisms already be dead in the bag?

Click to expand...

Live sand is supposed to have the anaerobic bacteria to reduce nitrates plus is calcium carbonate based to help buffer calcium. Crushed coral is also supposed to buffer calcium but is the "dreaded" nitrate generator because stuff decomposes in it. I just use plain old play sand in my tanks.



3. If I decide to grow corals, is actinic light needed? I hear it helps with photosynthesis but it is not needed. Will 6500K lights only work? And also how many watts per gallon is needed for with or without coral. I am used to freshwater needing 2-3 watts per gallon to grow plants, and dont know if it is any different with SW.

Click to expand...

 actinic lights are the spectrum of light below 30' or more. Some some deep water corals and corraline algae do better with them. 6500K won't look like your scuba diving at 20' but can look nice.



4. I heard there's many colors of Coraline algae. I want as many colors as possible, where do I get this? Petsmart and Petco sell them?

Click to expand...

 both macro algaes and corraline will have different colors depending on the lights used. Just experiment and see what you get.



5. I am keeping a 20g Long so I am interested in small fish such as clowns, gobys and wrasses. Any restrictions?

Click to expand...

* basically small fish.

Look what I do with marine tanks is basically a marine equilivant to a FW planted. Start the tank with macro algaes, let it set a week, then add a single male molly. Don't add foor for a week then add a female and start very light feeding.

Then after a few months try clowns, corals and so on. Anemonies (spelling) require high lighting so I would stay away from them. 

Some corals/filter feeders also need food like live phyto (micro algae) and rotifers. They are very easy to culture.

I would also research the DIY dr randy holmes-Farly improved 2 part. That will keep calcium/alk/magnesium up to help support corraline algae and hard corals.

just my .02


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## tinman (Nov 3, 2009)

Bealsbob 

you mean playsand from homedepot as the base and then the live rock on it ?? 

and iive heard we dont need mechanical filtration in saltwaters, just the bacteria in the live rock takes care of it. is this true ? 

and how exactly do we know if the live rock is alive or dead ?? 


thanks  


im just building my knowledge base (sometime soon im getting into saltwater for sure )


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## phys (Feb 4, 2011)

Here's what i've done and learned on my 20g to answer your questions:

1) The bacteria on the live rock will help establish your tank faster. It will take much longer for bacteria to just come out of nowhere if you dont have something that has it on there already. The live rock can also contain some invertabrates. The bacteria do the same thing as it does in freshwater, it controls the nitrogen cycle. If you have enough of it, it will also help with nitrates but if you have too many fish or feed too much, your nitrates will get too high.
2)It does matter a bit on the substrate. The live sand is basically sand with bacteria on it. Live sand isnt needed unless you want to start your cycle faster. Crushed coral is good because it helps your tank buffer the ph. beaslbob is right though, it can be bad, IF you put too much sand in. It can create anearobic spots in the sand that can become toxic. The easiest way to comabat this (if you want sand, which you dont actually need) is to get sand sifting invertebrates i.e. shrimp, conch snails, sea stars. Some people even do sandless tanks.. so its an option.
3)Actinic light isnt needed but it does help a lot. 6500K lights will not grow coral as well as a 10,000K light. Lots of coral live 10-30 meters under the water where the water has filtered out all the light except blue wavelenths. So the coral have evolved to use these wavelengths more than red. You will need more light than you have on your planted tank. Probably about 30% more lighting. But you can start with what you have (as long as you use 10,000K or higher, if not, you'll definately need more light at 6500K) and see where that leads you.
4) I dont think petsmart or petco has coraline algae, but that doesnt mean they dont.. you'll have to see. Be careful because some fish and invertabrates eat it. You can get some online or see if any local sw aquarists have them.
5)Some wrasses are coral eaters and aggressive toward other fish. So be sure you ask about or research the type of fish you want. Gobys and clowns are good though. You'll need to make sure your tank is fully cycled and only add 1 or 2 fish at a time. If you dont want any external filtration, restrict the number of fish to 2-4 in your 20 gallon. 

You can cycle without fish, its probably easier and cheaper. A lot of people use damsels to do it and you'll have to return it because they are aggressive and territorial. While you cure the live rock in your tank, it will have enough die off that you wont have to put a fish in there for the crap it will produce. If you get fully cured live rock, it will make the cycling go much faster and you'll be able to have fish in a week or two. If you dont, expect to wait up to a month or more.


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## beaslbob (May 29, 2009)

tinman said:


> Bealsbob
> 
> you mean playsand from homedepot as the base and then the live rock on it ??


Yep.


> and iive heard we dont need mechanical filtration in saltwaters,


yep


> just the bacteria in the live rock takes care of it. is this true ?


Nope. Not the bacteria but rather the algae IMHO


> and how exactly do we know if the live rock is alive or dead ??


 you look at it. the algae (corraline and macros) plus pods/corals make it live


> thanks
> 
> 
> im just building my knowledge base (sometime soon im getting into saltwater for sure )


welcome and my knowledge base always increases


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## tinman (Nov 3, 2009)

cool thanks bealsbob and phy 

answers help a lot 

so get the salt to required salinity and dump the sand and live rock in there and leave it for a month and i have a cycled tank ??

asking cause i have a 16 gallon fw im currently using to try breeding gbrs but really not that into breeding  im always changing my mind about things 

and i would leave on a vacation for 3 weeks some time june soo if i get the live rock and saltwater before i leave the tank would be cycled by the time i come back ?? 

i dont know what i will be doing after its cycled but for anything cycling is the first step right .....


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## phys (Feb 4, 2011)

that's exactly what you have to do to cycle/cure the rock and sand. BTW, you'll need AT LEAST 1 lb of live rock per gallon, more is useful though. I have 28lbs in mine. You'll also need to put a powerhead in the tank for circulation. You'll need 2 anyway so it'll be used later. So yes, depending on the level of curing that the live rock has gone through, it could be cycled by the time you get back. 

After you cycle the tank, add your cleaning crew i.e.: snails and crabs.
After a bit of time with those, you can add some easy fish or coral (if you have the right lights for corals). You'll have to wait a bit for some fish because they need algea and/or copopods in the tank to feast on. So be sure you know what they eat before you buy them.


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## beaslbob (May 29, 2009)

tinman said:


> cool thanks bealsbob and phy
> 
> answers help a lot


welcome


> so get the salt to required salinity and dump the sand and live rock in there and leave it for a month and i have a cycled tank ??
> 
> 
> 
> ..


No. That tank can have whatever in it for ever yet still not have buildup bacteria/algae to consume the algae. So then you add fish and they all die in 4 days.

With or without live rock what IMHO need is the algae. If you start the tank with a refugium full of macro algaes then let those get established and growing that will make a world of difference. Same thing if the rock is fully "curred" and full of algae. I just find $5 worth of macros or locals giving you some they harvest each month is much better.

So you setup the tank with the macros then wait a week. then add a single male molly and not add food for a week. Then start feeding a single flake per day. that way you build up the bacteria while the macros are keeping ammonia/nitrItes undetectable.


my .02


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