Sorry I haven't been around much lately. My full time job has busier than a one legged man in a butt kicking contest and I also work at the lfs on the weekends. I have had a run of bad luck lately. I attribute it to the heat, but I don't know. I have lost both my blood parrots and my female krib. They were all in the 135 gallon which I do a weekly 50% water change on. The temp has been 86F and possibly higher before I get home to turn the swamp cooler on or open the windows. I haven't lost any fish in the 50 gallon (86F) or the 29 gallon (80F). I'm baffled and getting a little upset. Any help or advice would be greatly appreciated.

I personaly think you are changing too much water at a time. I would not say that 86f is too high as to cause a problem like you are describing, what have your water stats been reading at ?

My tanks are overcrowded, so I do 50% weekly to keep anything from going bad. I haven't had a problem for quite a while doing this, its only been recently.
Tank inhabitants in the 135 gallon:
3 2" gold severums
2 5" geo. surinamensis
3 5" satanoperca jurupari
5 2" CLs
1 2" kribensis (there was 2)
there was 2 5" blood parrots
1 5" senegal bichir
1 2" knight goby
3 3" rainbow cichlids
1 4" bala shark
2 2" bala sharks
1 4" featherfin syno
1 2" syno. angelicus
1 2" L129
1 2" L27
1 2" L333
1 2" L260
1 2" L127
1 2" L174
1 1" L187b
1 2" L104
1 2" L002

Filters get cleaned weekly and consist of 2 emperor 400's and 2 powerhead 802's with quick filters. The filters don't get cleaned at the same time either. You would think if any of the water parameters were out of whack that the cls and the L174 would show signs of it. The dead fish look like they are still alive, but not moving. I'm treating with Melafix for a week to see if any of the new fish brought a bug in with them.

ph 7.2
ammonia 0
nitrite 0
nitrate 5
temp 82.5F

Water stats look very good, wondering if it could have anything to do with a lack of oxygen during high temps possibly when lights are out if the tank is well planted, remind me do you use co2 injection ?

No CO2 injection. I have 2 6" bubble wands and one of the powerheads is being fed via a pump also. No lack of oxygen in the tank. I'm thinking it could be a bug that was introduced from some of my new fish. I'm treating the tank with Melafix now to see if it is indeed a parasite or something.

Possibly could be a bug that you have introduced by accident. How well planted is the tank ?

It's nothing like yours. I'll try and get some pics tonight.