Experiments with air powerheads

[kycoralhead]

I recently had a problem with a CO2 valve opening up and causing a large dip in the PH of a tank. I placed a powerhead and put the tube on it to suck air and turned it on full blast to drive out some of the CO2. In a day the PH came up to 8.3 and all the fish survived except one. I have trouble with low PH on any tank with a calcium reactor. I am wondering if there are any articles on using air to stabilize the PH in a tank. What will be the long term effect of my experiment. I put the powerhead on a timer and turn it on at night. I turn it off in the morning so the tank can clear and be viewed during the day. The PH is fairly stable at 8.3 so far. But it has only been a few days. One thing I have noticed on a larger tank I run the powerhead on all the time is the red algae is going away. I tried a lot of water movement in the tank, but until I hooked up the air to the powerhead the movement alone did not help the algae problem. Am I on the right track? What effect does the on and off cycles have vs the continous on powerhead?

 

[randy holmes-farley]

There are plenty of articles, including some of mine, that show that aeration is incomplete in many tanks, and that better aeration can help solve many pH problems, both with high and low pH. THis artilce discusses solving pH problems, and mentions better aeration:

http://www.advancedaquarist.com/issues/ ... 2/chem.htm

This article discusses issues directly related to CO2:

http://www.animalnetwork.com/fish/libra ... ordNo=2074

Thios article discusses the realtionship between pH and alkalinity, which is strongly impacted by CO2:

http://www.advancedaquarist.com/issues/may2002/chem.htm

There are more if that's not enough to satisfy you.

There is no drawback that I can think of to better aerating the water in a tank. The exchange of CO2 is fairly hard to accomplish. Far harder than exchange of O2 for several reasons. One is that there just isn't much CO2 in normal air, and seawater can hold a very large amount of it relative to other gases like O2.

 

[kycoralhead]

Thank you for the reply. I have looked at two of the three articles but all those formulas send me into space. I will print them off and try to study them so I can understand. Most of it looks like a foreign language! Can you have a PH of 8.3 and too much Co2 in the system? The reason I ask is after the Co2 incident the tank walls turned green and I thought it was excess C02 getting into the system. I also thought it might be live rock die off from the sudden dip in PH. Sometimes the valve on the C02 reactor stops dripping and the reactor goes dry, when this happens does the C02 from the bottle go through the reactor and (isn't it heavy) fall into the sump and into the water? Also I cannot find this anywhere - how long should you wait, or what parameters should be monitored before you start the C02 reactor back up after a problem like I just went through? I thank you for the reply and I think this forum is the greatest! I know you help many people and it is great to be able to learn from others mistakes and knowledge.

 

[randy holmes-farley]

Can you have a PH of 8.3 and too much Co2 in the system?

Yes, but you'd have to have very high carbonate alkalinity. An alkalinity of about 3 meq/L would be about appropriate for a pH of 8.3 when in equilibrium with normal air.

I don't know why you got an algae burst, but it could have been for the reasons that you suggest.

Also I cannot find this anywhere - how long should you wait, or what parameters should be monitored before you start the C02 reactor back up after a problem like I just went through

If the pH is not too low (above about 7.8 or so), and the calcium and alkalinity values are starting to drop below where you want them, then by al means restart the reactor.

I thank you for the reply

You're welcome.