I had very good results for 10 years keeping FA algae to a trace and underwater plants to a minimum using no chemicals. In my one acre pond I had 18 grass carp(too many since they took out almost all of the underwater plants). 20 KOI and 6 Israeli carp that controlled all FA except for slight traces. In those 10 years I had no extra offspring’s of the carp because they were controlled by LMB and pan fish. Not one chemical was used during this period. Then I had a winter fish kill about 4 years ago and you should have seen the FA algae come on my pond. I know people raise their eyebrows at this but it worked for me.
This is what the pond looked like during most of the 10 years.
