# oxygen saturation/co2 depletion



## coralbandit (Jul 29, 2012)

I'll start with Ilooked for o2 or co2 test kits today. No luck.I believe my tanks are over oxygenated and lacking "ample" co2.I have "mega overflows" on my 180 and75. They flow to sump filters with noise baffles that overflow a weir to four drip trays. After that the water overflows into first compartment of sump(area dedicated to pumps for skimmers/ or re-actors) where water level is always the same.This is because it overflows again to second compatment before going on its way. For my 180 double that!Thats 8 overflows for 75 and 16 for 180.Each time water breaks surface and has contact with "open"air co2 is exchanged for o2.My plants(simple low demand) grow in my 180 and macro grows in sump area of 75 filter.They grow well(no real complaints) but are not flourishing in my opinion.Maybe I'm wrong but I think my tanks would benefit from co2.The systems to employ co2 are pricey to say the least. A major investment for a unsubstansiated opinion(o2/co2 test would help).I have a chart from freshwater fish.com that tells co2 level according to kh and ph.According to that I am co2 low at least.My question is with such surface movement ,is it possible to raise my co2 with out changing either kh or ph , without adding co2 system.Next I heard of (used in other applications) co2 from sugar , water, and yeast(diy co2). Is this safe for aquarium use(long term) or are there side effects(besides no control of co2 volume)? I think depleted co2 is responsible for plant growth rate and a few other issues(possibly not co2 related, but Ithink so)? Does anyone else have similiar issues , or answer/or thoughts on my situation?


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## NeonShark666 (Dec 13, 2010)

Raising dissolved CO2 levels always decreases ph. The equation is as follows: CO2 + H2O = HCO- + H+ More H+ decreases ph.


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## jccaclimber2 (May 6, 2012)

1) Water agitation/surface area brings your O2/CO2 back to equilibrium. In the case of a non CO2 injected tank this will not decrease your CO2, although it will probably increase your O2.
2) There are tons more things to look at before moving in the direction of CO2 injection, which will also require a bit more setup than usual given your sump/overflow, etc.
3) The KH/PH chart is completely useless unless you have no other buffers (such as phosphates) in your water. Unless you are injecting CO2, AND putting your pH in a drop checker filled with water of a known KH reconstituted from RO/DI water, the results are not valid. The world would be better off if that chart went away.
3) What lighting do you have, how high above the substrate is it?
4) Do you use any other fertilizers?
5) What plants do you have?

CO2 is required in a high light tank, beneficial in some medium light tanks, and won't do much of anything in low light tanks.
There are plenty of nice tanks out there both with and without CO2.


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## coralbandit (Jul 29, 2012)

I'm high light by most standards.Simple plants;anach,hornwort,java moss and crypts.My tank is over stocked I'm sure.The owner of LFS#2 in my area says I'm probably not oversaturated.I don't fertalise(probably great source of my dilema).Not complaining with my results but feel I could do better (for fish and plants). Mostly this goes in a different direction with 75 sw reef.Both sw and 180FW are growing(I trade both fw plants and sw macro monthly). Just thinking differently(most think not enough o2).I probably will not invest in co2 for either. Just looking for insight and experience.I have not had good results with swords or anubias.I created a lot of o2 through many exchanges in filter, but besides night behavior of plants don't believe I'm helping co2 enough? Thanks, and say more if you wish.I'm always open to eleveting my keeping skills I also feel chart to be irrelavent.


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## jrman83 (Jul 9, 2010)

I agree with what JC has posted. O2 does not displace CO2. They both enter the tank the same way they do your lungs.

Curious about your light. Since you didn't list specs, what makes you think it is in the high region? If it is and you are not supplementing with ferts and possibly CO2 they may not be doing well. Ditch looking at the kh/ph/CO2 tank. It is WAY outdated and doesn't really mean much.

As far as CO2 for a tank with overflows/sumps, it will all be gassed out very fast unless you seal the system. I tried an wet/dry with CO2 on a 125g, didn't work too well. A DIY sugar/yeast system is only effective for at most a 30g tank.


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## coralbandit (Jul 29, 2012)

lights; 6 4'current tue lumen pro led(white{4} white bluefusion{2} ,2 4't5 and 2 @ 225 whiteblue led(pretty crappy{used as nightlight(24/7)}. I agree chart is bunk. I think I just need to fert.Been reading everyones post for plant growth with out co2.Sounds very reasonable(I need fert, if I am high light). Am I high light.180 g (6x2x2).Also if my tank would gas out additional co2 ;it doesn't gas out natural supply of co2?


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## jrman83 (Jul 9, 2010)

It will gas out CO2, but the surface action with the air gains some back.

Your guess is as good as mine on your light level. If you have pushed into a high enough PAR to be high medium/low high level, you may need CO2.

How long is your photo period?


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## coralbandit (Jul 29, 2012)

12 hrs full(all lights on) t 5 1hour more in am and 2hours more in pm.The leds are pretty bright. Iuse same (all white/blue fusion)6 on 75 reef and simple corals multiply regularly. I probably should fert(I feed my fish,why not plants?)


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## jrman83 (Jul 9, 2010)

As long as the LEDs are in the 5500-10000k range. Outside that may not be helpful a all for plants.


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## coralbandit (Jul 29, 2012)

They are in proper range.I just ordered fert (micro macro mix) you linked in different post.I appreciate your help.Is fert just mix and pour? and how much should I use on 180g? Thanks


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## jrman83 (Jul 9, 2010)

I think it is one drop per gallon. I just counted the drops into a measuring spoon to see what size it was and then used the measuring spoon. I would start with one drop per gallon and only do that 1-2 times a week at most. If any difference is to be seen it may take a couple of weeks to see it.

There are directions on their website.


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