So I was at Big Orange this weekend, and wandered down the pond aisle. They
had these blue dye tablets that contain "enzymes" to eat the muck at the
bottom of the pond. The idea here being, tint the water and your algae will
die. I have about 3000 gallons, so I bought enough for about 1200 gallons.

Results...

....either I have less water or these things really work...my water is very
disturbingly blue.
....the algae seem to be affected as just after a day and the water is tinted
but clearer
....the tables stain your skin
....the fish, frogs, etc do not seem bothered by the dye at all
....not sure I would ever do this again.

BV.