Co2/PH/water changes

[falcon]

My water is 7.8PH. If I bring it down to let's say 6.8 through the use of automatic pressure co2 system, what do you do for water changes? Obviously, you should try and match the PH. Do you use RO/tap water mix for water changes to match the PH? It is a planted tank and I keep discus there-community tank 120g.

If I set the controller for 7.8, I would imagine hardly and CO2 would get released as not to alter my PH.

Any clarification/input would be appreciated.

Falcon

[anonapersona]

When water comes out of the tap it typicaly contains CO2 and the pH is lower than water that has aged.

In my case, while the aged tap (and in tank water w/o CO2) is 8.2, the tap water is 7.6 straight from the tap. I add this to the tank and then add more CO2 to take it to 7.2, but the differences between the straight from the tap water and endpoint for the tank is not really so large, so I never worry about it.

[Godslayer]

My tank is 6.6. My fresh tap is 8.2. I do 50% WC every week without incidence to the fish. A compressed CO2 setup will drop the pH in a matter of hours. Remember that fish are exposed to pH swings in nature all the time. They handle it fine.

[falcon]

Thanks guys. I think you're right. There is always some room for error as you won't be able to match the numbers exactly. With little experimentation with aged water and r/o water I should come up with something.

According to my liquid pH test(not sure to what degree accurate), my tap is 7.6 and aged 7.8. I would want to keep the tank at around 6.8 or so with co2. I will do some experimentation when I receive my pH controller.

Falcon.

[Tempest]

Falcon-- I don't think you need to worry about matching the pH to do your water changes. None of the people I have read about seem to find it to be a problem and I don't do it either. My tap water is about like yours and I use C02. There has never seemed to be any problem. The ph stabilizes quite quickly after the water change and indeed the fish seem to like water change day the best of all.. :)