My 30 gallon has two goldies, a fantail and a comet. I test my water frequently, and have noticed a slight drop in PH. Its not drastic, but the PH has gone from 7.8 to 7.2. Thats a little low for my comfort. I tested the water from the tap, and it also is 7.2. I hate to add baking soda, although I know its a PH buffer, as thats just a temporary solution and anything you get at the lfs DROPS the PH. I had this problem once before and added Jungle PH Corrector and it crashed my PH to almost nothing and darn near gave me a coronary.

Should I just leave it alone? I did a 30% water change, waited a couple hours and tested it, then waited 24 hours and tested it again. Moby and Florence seem fine, but it kind of worries me.

The ideal pH for goldies is 7.4, which is the pH of their blood. If your pH is 7.2 out of the tap, I don't know if I would even bother.

Probably the pH has gone down very very slowly (unless you have recently done an extra large w/c)and because that very slow drop was only an algorythm of .1 or .2 and also not into the 6's or 5's the fish are okay with that.

7.2 is fine.

But you might want to watch that tap pH doesn't go down any farther or swing too wildly. I suggest keeping a record for a few weeks to see what kind of swings you are dealing with. We had a time here when the tap pH swang wildly between 6 and 8 so I still regularly check our tap pH. If it regularly varies you may be better off doing smaller w/cs and do those more often. Morning and evening 10% each time for example with a wider pH gap than .2.

The trouble with b.soda and the cheaper buffers is it is so hard to tell when their effectiveness is used up. And if you miss the moment, the pH crashes again temporarily which -longterm- makes for more swings. If you think you have a big pH problem its really worth investing in a pH monitor and adding crushed coral to your filter box.

A natural result of the nitrogen cycle IS slight lowering of the pH of a tank. With sufficiant buffer, though, this is rarely a concern. I agree with the others that you should continue to test and watch your pH - that is ALWAYS a good idea - but it is not worth trying to ammend it.

Do you have a gH or kH test kit? It might be interesting to see just where your "buffer" readings are - it might put your mind at ease (or, perhaps, find a reason to keep a close eye on the parameters.....)

Thanks everybody! I'm out of the strips right now that show the KH, but I will get some on payday. I didn't know that a slight PH drop was a result of the nitrogen cycle. I will definitely keep a close eye on the readings, though, although unless it has an extreme drop I really don't want to have to mess with it and get into the roller-coaster ride that Trinket mentioned. Crushed coral is a good idea that I've seen mentioned before on here. I'll check at the lfs and see if they have any, or look online.