hi !!!
i had a quick look at the other post you have...
i think flow might be part of the problem.
the return pump should be more like a quiet one 3000 and add a ball valve if the flow is to strong..
as for inside the tank.i would add 2 more pumps on a controler of some sort.
the old koralias don'r work well on timers,the newer evo ones are ok.
you could also get 2 or 3 more maxjets 12000 and shout the flow torwards the inside of the tank,not just the surface
for example i have 5 different power heads inside my 92 plus the return from the sump and my euphilias are doing great..
water is prety much like others said,i would only add:try to keep it at .026-027
temp is ok i'm at 77.5yself but 79 is ok..
and this is just to double check everything,make sure no heathers are broken or that something is letting off high voltage in the water,if they were all nice for a long time and then one day things don't look good !!!! somethings up
i will keep thinking about what could help you out
good luck /bonne chance
STEFF