Is base fert toxic to fishes in the event of leak?

[pulp2000]

Hi

Would like to know if base fert (common brands like JBL types) is toxic to the fishes in the event that there is a leak out from the substrate??

Thanks!

[budak]

if the brand is meant for aquaria use, it's no problem at all. Some base ferts may cause some cloudiness if it leaches out, but that should clear with a good filter.