I made the mistake of using root tabs but my substrate is too shallow, so they were leaching into the water column. I have 7 cardinal tetras and 1 nerite snail in 54L tank, they are fine at the moment. (This was supposed to become a species only shrimp tank soon but now that is on the back burner). This tank has been up and running for 5 months (ish) with no problems. LFS advised to remove the root tabs, gravel and water change. No need to use root tabs, just to use liquid ferts. 

Ammonia 0.25 spikes for the past 3 days. Each day water changed and went back to 0.  

This morning nitrites look slightly bluer than previous, did another water change, just tested again, back to 0 for both ammonia and nitrite. I compared the water from another tank and tap water and they’re all the same shade of yellow. 

So my questions are…

What do I do about the constant ammonia? Should I remove the tetras and snail (they can go in my bigger tank)? Remove the plants and then I can give the substrate a proper clean? I am running a sponge filter, will the remnants of the root tabs be in the sponge? Will the cycle be affected by any of this?

I’m not sure where to go from here and whether just water changes will be enough.

Thank you in advance

Root tabs leaching into water column