Major water quality issue

[6329liam]

Hi,

I am having an issue with my cold water fish tank.
I have a well established tank that has been going over a year, and I did a 100% water change for a deep clean. Normally I do a 30% one but on this occasion I never. Anyway the filter broke as I took it out the tank so I had to buy a new filter. I couldn’t soak the filter in the old water as that was thrown away.
I treated the water with normal tap safe and I added quick filter start so I could get some bacteria going. I have been doing tests and most of my levels are fine however my Nitrite level is extremely bad coming in at 6mg/l and my nitrate coming in at 119mg/l. Both are too high.
To solve the nitrate problem I took the advice from the Tetra website which advised to add Nitrate Minus into the tank which I did. Luckily that is working slowly. To solve the toxic levels of nitrite tetra advised I add Safe Start bacteria and Aqua safe to try and reduce the levels however it is not working. It also says to do 30% water change and to treat the new water which I’m also doing. I’m running out of ideas and I am worried about my fish. Please help! Please see attached results if said test

 

[HannahJo]

Sounds like you crashed your cycle when you did the 100% change + a brand new filter. Did you save the filter media from your old filter to put into the new? That is ALWAYS a good idea- that's where most of your BB live.
I would do a big immediate water change if I saw my levels of nitrite that high.
You are basically doing a fish-in cycle at this point. Lots of water changes and/or dosing with prime to keep water parameters safe for your fish. Adding the bacteria should give your BB a kick-start but that does not immediately cycle your tank.
Also, adding bacteria and/or AquaSafe will NOT combat ammonia/nitrite levels. You need to do water changes or find a product like prime that does take care of ammonia/nitrite (but even with prime you will have to re-dose so it's not a cure-all).