[pmchan]

Right now I have a 3 gallon picotope so I know any water changes can be much worse than in a larger tank. I test at least once weekly and everything has looked good although the pH has never gotten above 8, I've buffered but it just won't go higher (only buffered once a week though).
Yesterday when I tested I had an ammonia spike, .50, everything else looked ok, pH 8, nitrite 0, nitrate 0, calcium 450, I'm out of KH test kit right now so not sure what it is, but it has pretty much stayed 10 down the line.
I then discovered that my brittle starfish had died, thus causing the spike. I removed what was left, and did a 50% water change. My salinity is sitting at 1.025 btw.
I checked everything again tonight and my ammonia is back to 0, nitrites 0, nitrates 0, calcium 450, but my pH had dropped to 7.6.
Nothing is looking very happy right now, and I don't know what to do to get my pH up to where it should be.
I re-read the instructions on the buffer and will start buffering daily from now on to see if that makes a difference, but I'm worried about losing my coral at this point. We have another established tank and I'm wondering if I should move my coral over to that tank until I get the chemistry straightened out, or would that be too stressful?
Any suggestions?

 

[YodaHart]

It could be a build up of CO2 in the air that is causing the low pH. Did you have any more people in the house than normal? You may want to try to open some windows near the tank or put an airstone in the tank and see if the pH will raise again. With a tank that small even 1 more person in your house can cause a large pH drop, especially this time of year when we close up the house and run the A/C. When I would have parties at my houe it was normal for the tank to drop to a pH of 7.0 or less. I would just open the windows and by morning (after most of the people left) it would be back to normal.

 

[[email protected]]

I would think the ammonia was a bigger problem than the pH. 7.6 is only a click away from 7.8 which is okay if stable. I agree CO2 in your house can vary more than you would think, I use an airstone in my tanks occasionally and especially if no skimmer.

What's the bioload?

 

[YodaHart]

If you noticed the pH drop after the water change, then I'm guessing you may have also not aerated your new water before doing the change. Your animals are probably just in a little shock with the major water change and having your new water be so different than what was already in the tank. Make sure the water parameters stay stable and give it a day or two then everything should be back to normal.

 

[PuffyLuv]

Your kH is probably very low, causing low pH - it is very important to test for kH, noticed that was not included in your list of tests - it would be a very good idea to start testing for this! With a pH of 7.6, if you have not buffered since - I am willing to bet your kH will be very low, like 6...