Tank wiped out - mystery solved

Hi all,

My tank wiped out six months ago and I thought I would log the experience in
case it helps others.

My tank was doing very well - 80g with Clown fish, regal tang, damsels, two
blenny's, feather duster, urchin, royal gramma, Mandarin. Snails

All going very well, in fact the tank was four months old, I'd added the
fish a bit quicker than advised, but everything still went fine.

The beautiful tang got WS and then the rest of the fish either got it or
looked poorly, using Copper free WS treatment had no effect. Gradually they
all died over two weeks. All this time the water parameters were fine, I
couldn't;t figure it out. I could only guess a bacterial infection or some
chemical had got into the tank. The was frustrating thing was not knowing
what happened so I could make sure it didn't happen again!

Anyway I was taking the tank apart a few weeks later and I found the
problem. My thermometer is for a marine tank, its a digital model that hangs
outside with probe inside. It has an "in or out" button or measuring the
temp from probe or the meter itself. Because of where the meter was mounted
the "outside" temperate was always about 30, because its near the lights. I
forgot that a few weeks previous to the wipe out the tank temperature was
high and I turned down the tats to help this, it didn't;t work and I assumed
it was the lights keeping the temp up.

Anyway, you guessed it, I thought I was monitoring inside temp but the meter
was switched to outside! The water in the tank would have been about 18 - 20
Giving the fish a slow death :-( While I thought the temp was 30!

Les