Erratic swimming and floating

[falconrob]

I have a 125 gallon aquarium held at a temp of 78 degrees with the following fish: 1 bala shark, 4 tiger barbs, 5 white clouds, 5 zebra danios, 3 lemon barbs, 2 placo's, and 2 upside down catfish. I have plants on the left side of the tank for hiding and a barrel on the right. In the middle I have a river scenery thingy that pumps air into the tank. The tank is over 3 months old, I have changed water and gravel cleaned several times. I just had my water checked as I do every week and all looks good to the experienced fish store person. The only thing we found abnormal is the ph. It appears to be high. Two nights ago I treated that with the correct chemical to bring the ph down.

My problem is: I used to have gourami's (4 to be axact, not all at the same time). I tried having 2 at a time. They eventually all dies the same exact way. They began swimming in fast circles and bumping into the walls. When they weren't doing that they would lay down somewhere in the tank till I tried arousing them and they began the bouncing around again. To move on, I assumed it was over until it began affecting other fish. I have lost a tiger barb to this, a bala shark to this, and 2 lemon barbs as well. I have tried to put salt in the water inside a bowl for stress and the water tests showed it had normal salt levels. I have put my arm in the tank to remove dead fish and to put in and remove some squash for my placo's.

I am confused! HELP!

 

[SCU33ZE]

When you say high.... How high exactly, also the chemical you used may have lowered the ph too fast and shocked/stressed the fish. It's better to have a steady high/low (not extremely) ph rather than a bouncing up/down ph.

Have your KH tested since your ph is high this must be high aswell.
"experienced store person" forgot to tell you that you must bring the ph down slowly (if you had to)so that you dont shock your fish.

Also is this tank cycled?

 

[falconrob]

The ph was off the chart, like a flourescent pink. It wasn't even a value on the bottle.

It makes sense to bring the ph down slowly. I think I was too much in a hurry to help them I may have done the opposite. So far the fish are still alive.

I am unsure what you mean by cycling. If you mean how are my weekly waters tests going, they are all ok. Had a high ammonia weeks ago but steadied that out by my feeding schedule. I was feeding too much. If you are referring to the cycle of the tank, I believe the fish person said I was evening out after growing good enough bacteria and getting my levels into spec.

I apologize for not having the right lingo.