Ammonia Question

[Benunited]

Hi folks

Quick question about ammonia.

I recently (I think) completed the fishless cycle for my 2nd tank - getting 0 ammonia, 0 nitrite and trace nitrate levels continuously before adding fish a couple of days ago.

This tank is a 30 litre biorb which I'm using as a quarantine tank before adding fish to my other tank, which is fully fishless cycled and has been running well for a good few months now.

From past experience I know the tank can safely handle 8 small fish - it used to hold 4 guppies and 4 cardinal tetras and never had any ammonia or nitrite once it was cycled.

Now I've restarted the tank, completed the cycle and added 8 tetras.

Trouble is my tests are now showing low levels of ammonia. What's puzzling me further is the nitrite reading is zero (good!) with low nitrate levels.

So, if the tank is fully cycled, what's happening.

Can I have some ammonia, no nitrite yet some nitrate? Well, obviously I can... but why has this happened and what can/should I do?

All advice much appreciated.

Thanks!

Ben

 

[OldMan47]

You are in the very beginning of a fish-in cycle. Your new fish are producing ammonia that the bacteria cannot deal with. The end result is a slow build of ammonia with no processing forward to nitrites. The answer, in terms of fish care, is to do massive water changes so that the new tank's water never shows more than 0.25 ppm of ammonia or nitrites. It is not the elegant answer most of us would like, but it is an answer that will allow your fish to survive and thrive.