Question about pressurized Co2, Ph, and water changes.

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When I start to inject pressurized Co2 into my tank it will lower my ph greatly. I’m concerned that when I do a 50% water change the ph will swing and harm my fish. The ph of my tap water is 7.8. I plan on bringing the ph down to 6.8-7.0 in my tank. How can I do a water change without causing the ph to swing?
 
Do not worry about ph swings. ph swings due to CO2 injection will not hurt the fish. The only ph swing that will hurt your fish is if your kh/gh is swinging, which also causes the ph to swing. I have mine down at 6.4, and when I do my PWC, it swings quite a bit, up to 6.9 sometimes, but it's perfectly safe. As long as your kh and gh are stable, and your ph swings due to CO2, you are just fine.
 
Lonewolfblue said:
Do not worry about ph swings. ph swings due to CO2 injection will not hurt the fish. The only ph swing that will hurt your fish is if your kh/gh is swinging, which also causes the ph to swing. I have mine down at 6.4, and when I do my PWC, it swings quite a bit, up to 6.9 sometimes, but it's perfectly safe. As long as your kh and gh are stable, and your ph swings due to CO2, you are just fine.

I definitely won't be messin with the gh or kh.

But doesn't the kh get lowered as well? The kh in the tank water wouldn't be the same as the kh in the tap water. Would that cause the kh to swing?
 
Unless you are adding chemicals, crushed coral, or baking soda, your kh should remain stable. Shouldn't be much of a difference between tank and tap. And no, adding CO2 does not change your kh or gh. Just the ph. As long as you aren't adding anything to the tank other than dechlor and ferts if you are dosing them, you are fine.
 
Lonewolfblue said:
Unless you are adding chemicals, crushed coral, or baking soda, your kh should remain stable. Shouldn't be much of a difference between tank and tap. And no, adding CO2 does not change your kh or gh. Just the ph. As long as you aren't adding anything to the tank other than dechlor and ferts if you are dosing them, you are fine.

Oh I thought for some reason co2 lowered the kh :oops:.

Thanks a lot Lonewolfblue!!
 
Just one last question, I was wondering if the tubing used for the nutrafin co2 system is co2 proof? I was thinking that instead of buying new tubing I could just use the tubing from the nutrafin system. Also is it possible to get check valves at local hardware stores?
 
yes the nutrafin kit uses CO2 grade tubing. its good stuff.

i've never seen a check valve at a hardware store...least not one small enough for CO2 airline.

just get a plastic one for $1 at the LFS, and replace it every year.
 
malkore said:
yes the nutrafin kit uses CO2 grade tubing. its good stuff.

Great!

malkore said:
i've never seen a check valve at a hardware store...least not one small enough for CO2 airline.

just get a plastic one for $1 at the LFS, and replace it every year.

I didn't think my LFS would have had check valves. I gonna pick one up tomorrow.

Thanks malkore!
 
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