toxic tank now what?

well we had a huge LTA go missing over night. 2 days later the tank started to get ick. then it started dying off one by 1. only inverts a blenny and an eel remain. since then i took the rocks out an inspected them all VERY closley. i found 2 rocks with unknown goo on them. i removed those rocks and am in the midst of a very long cleaning process of bleaching and boiling. i drained the tank and siphoned the sand out with a gravel vac. and refilled with fresh salt water. i am now running a carbon reactor plus the skimmer plush a hob filter with carbon, poly filter, purigen. i also added live bacteria at 2.5x the instructed dosage.

what now ? the tank is still killing fish. i put in a neon goby and it lasted 3 days then died. any ideas what else to try?

 

How long after refilling the tank did you add livestock?

 

Exactly what I was going to ask. If the tank didn't re-cycle, anything added will probably die.

 

it tests 0 ammonia 0 nitrites... the rock never dried out i took a rock out inspected put it back. drained the tank siphoned the sand and filled up immediately. but we waited 2 weeksish ? lol

 

Ah, there inlies your trouble. Two weeks a cycle does not make.

 

i dont c y it would cycle? theres still 0 ammonia nd nitrites.nd a damsel should b tough enough to make it through a cycle neway. the ammonia nd nitrites r the big killers during a cycle and neither is presant so i dont get it ....

 

I take it you have another tank for the livestock?if so i would move them there,throw a peice of raw shrimp in for the bacteria to feed on,multiply and start a hard cycle all over,cause it sounds like you took the right steps to clean it up,but mabey it's to clean(i'm not convinced of bacteria in a bottle)I could be wrong,but just my 2 cents

 

perhaps something in the tank is killling the fish? maybe you got a hitchhiker? or maybe that eel has been busy?

 

If you boiled your rock, it is full of dead stuff and will have to be re-cured. About a 2-3 week process. While you are doing that. Let the Purigen and Carbon do their thing. Then return the rock, and start with a Damsel or two.

 

"drained the tank siphoned the sand and filled up immediately." Say what? O.k. perhaps you really don't know. The sand and water hold a lot of bacteria, removing that much of the biological filtration will surely cause another cycle. You may be experiencing Ammonia spikes and you happen to be catching the Ammonia at 0.