Help Nitrite Gone Sky High After Changing To New Tank?

[craigybaby37]

done a water test last night and to my supprise the nitrites are sky high and realy dangerous for the fish. when i only had my rekord 60 on the go everything was perfect but on friday got a rekord 96 and changed the fish into this with about %80 of the water from the rekord 60 i also planted out the tank sunday so i cant see whats causing the problems?? have checked the filter system and everything is fine....after i cleaned out the first white cotton sponge now the water filters through realy well could this of been causing the problem and how long will it take to clear?? i cleaned the filter out last nght by the way.

any help much appreciated