Planted Tank Guru
Join Date: Nov 2009
Location: Missouri united states
Would give the tank time to run sans fish until plant mass is thriving.
The worm casting's (poo), are rich in organic matter and this could very well produce ammonia for a few week's in excess of what fish may tolerate.
Should one choose to place fish in straight away,,I would suggest heavy plant mass,and monitoring of water for ammonia and perform water changes as needed with dechlorinator such as PRIME which can detoxify ammonia and nitrites for around 14 to 24 hrs.
Lot's of plant's will also use up ammonia much better than just a few plant's.
I tried the worm casting's once mixed with topsoil,sand, and Azomite as expieriment.
Plant's performed well, but I think the metal content in the azomite had negative effect on the few fishes I placed in the tank,but I have no scientific evidence to prove this.
Could just as easily have been ammonia spike between near daily water changes to try and keep it in check.