something is killing my fish

[trigger gta]

I think there is some disease or poision in my tank that kills any fish i try to add. in less then 24 hours with no signs of trama.

here is the short form story leading up to this

-tank info is 275 DT with a 225 basement sump.
-tank was been running for 11 months
-3 months ago i had a ick brake out and removed all fish for QT. the remaining fish went into a seperat system (90g, they are still in there now) untill my main was ready
-10 weeks fish free i bought a wrasse and a few anthias. i added them to my qt that i used water from my main system to fill.
all died in less then 2 weeks.
- thinking i did somthing wrong in QT i added a clown and a yellow tang to my main tank that has now been without fish for 12 weeks.
- lost them both in only a few day.
- i stripped down my qt tank and cleaned it all filled it with fresh mixed salt water. let it run for 2 weeks and added a dottyback that is doing great.
-i started a second qt system using tank water and added a yellow tail damsal. that did not make it 24 hours.

to me it says somthing in the water. but i also want to point out that the snails/ shrimp/ crabs and coral are doing good. it seems to affect the fish only

what i have ruled out for being the problem

-water sourse/salt and food. (all are being used on my 90 with no issues.)
-some kind of preditor. ( only water was moved to the QT tanks)
-basic water quality. i have tested my water for amiona/ph and all the other basics countles times as well as independent test from 2 LFS to back my test up

i really am at a loss for what to do at this point other then draining it all and starting fresh

 

[snorvich]

SG of tank? SG of LFS bag water?

 

[trigger gta]

i keep my tank a .024.

i dont know what each of the lfs were at

 

[thor109]

That is a tuff problem. Sometimes fish die. Maybe you had a fluk two times in a row. All I can suggest is buy 6 cheap fish and quarantine. Do some water changes on DT and add them all and see what happens. Unless you know you did something like use a bad silicon or put something else in the system that is really all you can do.

 

[trigger gta]

dont think i did anything wrong like bad silicon becasue i did go 7 months with fish and no issues untill i desided not to QT a fish that was to big.

i also dont think it was bad luck i have tryed fish from 2 diferent stores and 1 friend. all end up dieing .

i bleive it might be somthing in the water

 

[snorvich]

i keep my tank a .024.

i dont know what each of the lfs were at

Many LFS keep their water at a low SG in order to save on salt. That could be a problem if you are not equalizing SG.