Question:
I want to change from the fairly sharp slate chips, rocks etc we've got now, to some softer gravel.
Would I be better moving the fish and water to containers then doing it, or attempt an "in Situ" ?
Answer:
The one concern with changing the gravel in place, is that you might stir up
some nasties (Hydrogen Sulfide) that could harm the fish. If you do change
it with the fish in the tank, do it over a few weeks. Remove a few cups of
clay chips each day. Then add your new (washed) gravel.
