Low pH

[Jyman]

Ok the pH of my tank is sitting at 7.8-7.9 and I have tryed using a pH upper and I have tryed using 1/4 tsp of Baking Soda. but they have not changed the pH of the tank.

Am I not using enough Baking Soda? o and its a 55 gal tank.

[Myka]

I wouldn't mess with the pH directly like that if I were you! You can use baking soda to up the pH, but it will fall right back down to where it wants to be. 7.8 is not an issue, no need to panic, no need to even bother to change it. I don't even test mine, mostly because pH test kits are unreliable (digitals are much better), but also because if everything else is on target, the pH will follow. A steady pH is much more important than the "proper" pH, and using baking soda or any other buffers that directly alter the pH will cause your pH to fluctuate. That's not good.

Do you have a refugium? By adding a refugium with chaeto and having the lights on when the tank lights are off will help keep the pH from falling at night. This effect will usually raise the average daily pH as a side effect.

Do you have a skimmer or calcium reactor? Often low pH is caused by high dissolved CO2 (often just from having CO2 in the house from breathing and not having open windows). A skimmer helps to off gas CO2 (an airstone will do the same thing). This is why it's also important that you don't have a greasy protein buildup on the surface of your water. Gas exchange. If you have a calcium reactor, double check that CO2 isn't escaping into the tank. I've heard of the odd person having this issue.

Another thing that will lower pH is high nutrients. If there is a large amount of organic matter breaking down in the tank and going through the nitrogen cycle your pH will drop. A good indicator is the level of phosphate particularly, but also nitrate and/or nuisance algae.

[Jyman]

there is no refugium or calcium reactor.

but there is a protien skimmer, and the tank is part open and part closed. there is some uneaten food that the RBTA could not grab.

could the un-eaten food be the problem?

[Myka]

If it has built up over time, and caused your tank to have high nutrients then that is possible, but my point was that 7.8 is not a problem. :)

As easy test is to take a good sized air pump with a ceramic or glass diffuser (not a cheapie stone), and let it run for 24 hours, then re-check your pH (at the same time of day you made the first test). If your pH has risen then the cause is excess CO2 in the tank. If the pH doesn't rise, then it is something else.

[Jyman]

ok thank you Myka