How long should theses units run for

[humerjeep]

I have a Nutrafin C02 unit, although it was only setup yesterday, I have yet to see if it is functioning properly, but my question is how long should this unit be on each day. I read somewhere (cannot remember doing too many searches) that these units should be disconnected at night or the gases will suffocate the fish is this true?, also I have read a few of the threads on this site that C02 will lowered PH levels an KH level what are the later and how do you test this? and if C02 units lower PH level could this affect live stock within the set up, I have just started a new setup and going through the cycling process so this is not a problem as yet.

[Roan Art]

You need to buy a KH testing kit and will need a pH kit. You really should not be injecting CO2 without those.

Roan

[humerjeep]

Thanks. So should I disconnect the unit?

[EcoPit]

My impression is that most folks using DIY CO2 or that product do not disconnect at night. Many (but not all) folks using pressurized CO2 do turn theirs off at night. Leaving it connected certainly will not suffocate the fish because O2 levels in the water are independent of CO2 levels. Some don't like the pH swings that will happen if you turn it on and off. I partially don't like the pH swings, partially am just lazy, and partially think that unplugging DIY will require time for it to re-pressurize and start bubbling again when you hook it back up in the morning. There was a recent thread debating the issue and it seemed to be pretty much split both ways, so do what you are most comfortable with.