My fish tank was looking quite sparse, so i decided to give it a full clean out. I took all the water out and into a new tank along with the fish. I cleaned out the tank, including replacing the gravel. I put the fish back in with the original water as i knew this was important due to the good bacterias etc. What i did not realise is that most of the bacteria is in the gravel and the filter, and i seem to have removed this all. So i got some water strip testers and my nirite levels are as high as it goes and nitrate are 2nd from highest it seems, maybe highest also. But i remember testing my tank a while ago when it was all set up and i had the same issue, lots of nitrites and nitrates. But the fish never seemed to care and they dont now. My tank has always been quite a self cleaning tank though, i rarely cleaned the filter and it just seemed to plod itself along. But ive realised i need to get this bacteria going and the external filter should help. Also, in the past ive never used conditioner, so maybe my water could have had chlorine in it and killed the bactera? Ive also got some API quick start. i just want to check can i add the quick start with the fish already in?

Ive learnt everything i know so far from my father who seems to have had a good past with tropical tanks, but there seems to be so many things popping up that are big no no's, such as changing water with tap water etc.

Any help would be much appreciated, thanks.

Also anybody got any other ideas what i can do to resolve this problem and possibly get some healthier water.

Hi

We have an article here which explains what to do in this situation: https://www.fishkeeping.co.uk/articles ... ammonia-nitrite-spike.htm