Stephen Henning wrote:


New concrete turns the water alkaline. Let it age before use. Or roll on a
coat of asphalt emulsion.

Asphalt emulsion is can suffocate fish until it completely cures.

Same question, but slightly different angle. I am converting a pool
(shotcreted and plastered in 1987) into a pond. The plaster is now
off-white with years of dirt, scrubbing, and algae and slightly
pockmarked. I was thinking of coating this with epoxy paint (black or
dark blue). Any fish problems with that?

Chip