PH Controller Required for compressed Co2?

[JJM]

Hi all! I'm a new discus keeper but I've been doing plants and other fish for a while.

My question is: Is it ok to run a compressed Co2 system with solenoid on a timer with my lights? or will this be very tough on the discus with the shift in PH in the day vs night?

I have a single 3-4" red turq in a 29 gallon planted tank with 20 cardinals, 6 ottos, 2 fat SAE (who are getting the boot soon, the pigs!) + some unwelcome snails.

My water is pretty hard at KH 16, PH~8 from the tap.. I think the Co2 brings it down to about 7.2-7.4

I dont really like the idea of running the Co2 with the lights off with a PH probe / controller but if the Discus need it.. I've gotta do what I've gotta do. ;)

any advice would be greatly appreciated!, I'll try to post some pics of this tank later on.

[Don_Lee]

Definitely do not have to have the pH controller, is nice to have but not absolutely needed. You should do fine with the setup that you have described, with that much KH you will not have to worry as much about a pH drop as you would if you had soft water.
Maybe a loach would help with the snails, the dwarf loach stays small and I think it eats snails as well. Might want to check that out to make sure....
Looking forward to seeing some pics!

Don

[Anonapersona]

Before you invest the time and money, test to see just how much your pH is actually changing from morning to later afternoon to evening to morning. My water is not as hard as yours and I saw very little change.

Those controllers have to be kept calibrated as they shift over time.

[shalu]

ph change due to CO2 level change is not going to kill your fish(ph crash due to low kh is another matter). I agree with Don, controller not required. Although I have used a controller for almost 3 years now, I feel more and more strongly that it is not needed. But a ph monitor is very useful. I actually now hook it to a timer and stop CO2 at night. Yes, there is ph swing like 0.5+, but discus say who cares. Sometimes it can do more harm than good if precautions are not used. Folks who have controller tend to be very generous in terms of CO2 bubble rate, thinking the controller will take care of everything. Well, kh in water souce can and do change. Suppose you initially set ph at 6.7 with kh 4, everything is fine. Now your water company decides to increase kh to 10(happened to me, but I had precautions in place), all of a sudden, you are injecting FAR more CO2 than you planned to.

[JJM]

Thanks for the feedback! Good point about the possiblity of unstable hardness shalu.

as promised here are a few pics, any comments on the type of discus this might be or if it looks stunted would be appreciated as well. :o

http://img31.echo.cx/img31/3516/img05322tk.jpg (http://www.imageshack.us)
http://img31.echo.cx/img31/7127/img05334oy.jpg (http://www.imageshack.us)
http://img31.echo.cx/img31/5926/img05379nb.jpg (http://www.imageshack.us)