Question
How long must we let the water set in our pond prior to adding back our fish, after filling with city water?  We would rather not add any kind of chemicals to clear the ones added by the city supply.

Answer
Hi Gary:  That would depend on how much of the water volume was replaced with new water... for a partial water change of 30% or less I would say... 12 hours... everything else would be about 24 hours... that is the amount of time for the chlorine to be dissolved and absorbed by the oxygen at the surface of the pond.... dave