That's a lot of livestock to add at once. The presence of nitrite indicates a cycle has occurred meaning that it could have been ammonia.

I'd still crack the FX5 open and give it a sniff.

still just very odd to lose all the fish overnight and the corals are still alive. some more investigation is needed i think.

AlfredsHouse
 

The ammonia was at 0.0
Nitrate was at .8
I know it was alot of fish at once, but there were only 3 in there and I didnt expect them all to die.
I opened the FX5 and it didnt stink like rotten eggs, Checked it two weeks ago.
I did another water change tonight, I changed 50% and the KH is still high, its at 140, with a safe range of 100-125,

Im going to take my water to AA tommorow and get them to test it.:cry::cry::cry::cry::cry::cry::cry:

this may be a stupid question but whats the temp? Any chance of a heater malfunction?

Alfredshouse
 

Tested for voltage in the water, none was found
Did a water change on Saturday.
Please give more suggestions, Thanks

how long has the tank been up?

Tank crash
 

Temperature is/was at 79.6 and its been up since Feb/08.

Tank crash
 

tested the inliner heater and digital thermometer and they are working. I put another Koralia in this weekend, thought that might of electricuted everything, but nope thats not it either.

Your water parameters seem to be fine. At least not to the point that it would kill everything overnight. It almost sounds like you might have had a CO2 build up. Using a cannister doesn't agitate the surface so this might have been the cause.
Just trying to help narrow down the possibilities.

You keep saying Nitrate - which is not really toxic to fish.

If you say Nitrate (No3) being 0.8 - I think you mean Nitrite (No2) - which is very toxic.

Sorry about your loss.

It was just too many fish added at once.

Bummer.