Is 8.0 too high a pH?

[FishieMomma]

My fish have been dying off because of two major ammonia spikes last month and an unexplained BBs die off. (at least I think that's why). I change 50% of the water most every day - never more than every other day as by then the ammonia levels reach .25ppm. Out of curiosity I tested my water's ph which had always showed a slightly high level of 7.4. Today it tested at 8.2! Could this new higher pH have killed off the BBs which may be partially responsible for the fish deaths?

I've heard adding peat to the filter can help with lowering the ph but will the resulting changes in pH from the tap, which consistently tests at 7.4, hurt the fish also? ETA: 55 gallon, was cycled for 2.5 years. Right now one Opaline DG, 2 Cories (there were more 3 neon tetra (thre were more of these, too. And 3 black neon tetras. Half planted with plenty of hiding spots between the driftwood (been in the tank for a year at least) and a few plastic plants with them.

Ammonia never at more than .25ppm due to daily testing and near daily 50% water changes.
nitrate always zer.
nitrate always 5.0

Could the higher pH deplete too much oxygen? I have two filters, an Aqueon 50, and an Aquaclear 50 plus a bubbler in the middle of the tank. Also a heater which keeps the tank at 78°. I do declorinate with Prime and temperature match.

 

[Khuligirl93]

Wow this is really puzzling... No way should you be getting ammonia with that few fish in a 55g that's been cycled for 2 years. I admire your dedication on doing 50% water changes every day- that's a lot of water! Has anything changed in your tap water recently? What are you using to test?
The pH should not be a problem. Consistent pH is more important than a perfectly neutral pH. Mine is about 8 as well and I have had no problems for 4 years.

 

[Jmunroe]

Higher ph will make the ammonia more toxic. But it does sound like a puzzling situation

 

[FishieMomma]

I do use the API Master Kit.

Something just occurred to me, a few days before the first ammonia spike I added 2 of the three large pieces of driftwood from the excellent LFS near me. All Mopani.

I know this can raise pH, but this much so quickly?

 

[FishieMomma]

I just occurred to me - I put some new, unglazed, terracotta pots in the tank at the same time I added the two pieces of driftwood (all a month and a half or so ago). Research on the internet gives me different answers a out the terracotta affecting the pH. A few sites mentioned those pots treated with lime may spike the pH. I have no idea if this applies to my tank at all. The pots were definitely unglazed.

 

[Khuligirl93]

Driftwood actually lowers pH. Hmmm I have put unglazed terracotta pots in my tank with no problems- I did rinse and soak them for a few hours though.

 

[FishieMomma]

Thanks for responding! While I did rinse the pots, I did not soak them. I also broke them into pieces to make tunnels and various hiding places. Perhaps breaking them and therefore having the insides exposed could have done it?

 

[Khuligirl93]

Haha I did the same thing! They make great pleco hiding spots
It was a while ago though, before I used a test kit. So, if it did do anything strange I probably wouldn't have been aware of it :/ sorry I can't be more help!

 

[FishieMomma]

After removing the terracotta my pH decreased from 8.2 to 7.6 within two days! Wow!