# Co2 on 75 gal



## RandallW201 (Jul 31, 2011)

I know its a loaded question because it all depends on your individual tank, setup, and how heavily planted a tank is but I'm wanting to know what bps i should be aiming for.

Therefore, if a few of ya'll with a tank close in size could tell me what you set you bps for I'd appreciate it.

I'm just trying to get a general idea on what I should be aiming for in this regard. Right now I'm running about 1 bubble every 2.5 sec just to ease into it and get it going as it has only been on the tank for a little over a week now.

I'd say its heavily planted, wouldn't you?

















Thanks Guys!
Randall


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## niko (Jan 28, 2004)

Depends how you disolve the gas.

The simplest in-tank diffuser is just any powerhead with the CO2 tubing stuck in its intake. And a sponge over the outtake. This setup disolves the CO2 almost 100% and it is very reliable.

That being said, with the above setup I'd run 1 bubble per second to start with. For a 75 it's on the low side. But read this:

Keep in mind that the people that run a lot of CO2 lower the pH of the tank considerably. The concern is not the fish suffocating but the biofilter operating in a bad environment. The organisms in your biofilter (filter media and tanks substrate) like a pH of 7.5-8.0. If you reduce the pH to 7 they operate about 50% of their max. At pH 6.4 they operate at a fraction of their max. 

All Japanese tanks maintain pH of 6.8. That is a compromise point between giving CO2 to the plants and not supressing the bacteria too much.

I told you all that so you learn some more details/considerations when asking about the CO2 level in your tank.

--Nikolay


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## RandallW201 (Jul 31, 2011)

Hmmmm, did not know that about the bacteria. Very interesting.

I'm running the CO2 through a GLA glass/ceramic diffuser and placed a powerhead directly above that to suck in the micro bubbles, chop them up more, and spit them out.
You can see it in the pic in the top right. BTW, most of those bubbles you see in the pic is oxygen running through the powerhead too.


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## geeks_15 (Dec 9, 2006)

In my 75 gallon CO2 tank the water is medium hardness (ppm 250). I use a pH probe with automatic shut off. My CO2 brings the pH down to 6.7 from 7.8 using many bubbles per second. I have a sump on this tank, so I lose some CO2 due to surface disturbance as water flows from the main tank to the sump. My diffuser is an inline type that is in the plumbing that takes water from the sump to the main tank. I fertilize using the EI method. I keep discus, blue rams, and a bushynose pleco in this tank and it has been going well with very nice plant growth for about 3 years.

Hope that helps.


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