Need Hlp Plz

[1life4dataking]

I had tested my water earlier today and the omon was 0 ppm the nitrite was 0 ppm I had a lil issue with my pump I added water I came back just a few min ago and notice one of my fish was dieing I decided to check my test agian and the omon was good but my nitrite was .25 ppm and my nitrate was high any info on what to do plz i could use some advice...

thnx to any 1 who replys

[CarpetAnenomes]

Where did u get the water for ur water change from? How big of a water change did u do?

[1life4dataking]

I got my water from an ro system and i did a 5 gal water change and my tank is 55 gallons

[abdhalim2]

test your RO water n get the results....i dont think it was came from the RO water instead....maybe other sources....

[Ant329]

Usually sounds like a tank thats not cycled fully.. Or something from a diff source was added

[Gregcoyote]

Are you being careful to match salinity, temperature and Ph in your exchange water? A 10% water change isn't too large, but a significant difference swing in any of the above could whack a fish. Water changes is the best way to correct an organic buildup problem the fastest and safest in my opinion.