I build ponds for a living... The best way to combat algae is to ditch the uv lights they just kill the BB.... Keep doseing your pond water with dry bacteria.. Dry bacteria is expensive but you can use ridx... It's basically the same thing.... We use it all our ponds and waterfalls we maintain...having alot of healthy plant life will help combat algae also.... But the ridx(dry bacteria) is the best way to having a very healthy pond... It won't bother the fish either
