[King Tut]

I have a 55 gallon planted tank, also running pressurized co2 at about 5 to 7 bps, and am also using the pps-pro fertilizing method. My question is concerning the co2 levels. I have hard water. GH about 13 and KH about 11, ph is always at around 7.4. If adding co2 is supposed to lower my ph a bit then why does my ph never change. I think it's because I have such hard water and the kh is high therefore to bring the ph down with co2 alone I would have to pump lots of co2 into the tank. I am however not trying to change the ph at all. What I was wondering is will simply putting co2 in the water and not knowing if the plants are benefiting from this or not. I think I am just wasting the co2. Maybe I can get away with less bps as there is now way for me to check the co2 level accurately enough. Using the kh/ph method always gives me the same result as to my co2 levels which are very low. As for the plants to get enough co2 and not changing the ph or the color of the dropchecker are concerned what do I do. Reduce the bps. The plants look good and yes I know that if they look good then things must be working. I guess I could reduce the bps count and see what happens. Oh I do have green hair algae that I have been trying to get rid of. Maybe adding some missing ferts will help. So the questions are not tank parameters or plant types of fish load or lighting or anything else. Just if you think I'm wasting the co2 when I can't or don't want to change the ph or kh (which is hard to do anyway and would hurt the fish trying to change things all the time).

 

[Hoppy]

Three things could be wrong: You could have CO2 leaks between the bubble counter and the tank, you could be agitating the water so much you are losing the CO2 from the water surface as fast as you are adding it, or your method for diffusing the CO2 into the water is extremely inefficient. The first is the most common problem. It takes a very small leak to keep you from getting the CO2 into the water. The last can be a problem unless you are using a known good design CO2 reactor.

 

[PerfectDepth]

^this. Also, try setting out a cup of tank water for 24 hours and then test for baseline pH. At 7.4 it seems there should be at least a bit of dissolved co2.

 

[nayr]

might get some calibration solution and check your pH testing kit and verify its actually what you think it is.

 

[Maryland Guppy]

Here's what I think your pH would be if CO2 were turned off.
This works out to about 13ppm CO2 @KH11 and pH 7.4

I have to go with Hoppy, leaks or poor reactor performance.

What type of reactor/diffuser are you using?

Bump:

^this. Also, try setting out a cup of tank water for 24 hours and then test for baseline pH. At 7.4 it seems there should be at least a bit of dissolved co2.

Place an air stone in the cup for 30 minutes to degas CO2, then read pH.

5-7 bps could be a lot or little CO2, depends on orifice diameter of tube entering counter.