This is my experiment with a floating garden used to keep algae growth down, fish protected from predators, and a notend vegetable garden. See details at https://www.diymarta.com/floatingbio...

Other products that reduce algae in mucky ponds (affiliate links):
Barley straw "bales" https://amzn.to/2AWI8SX
Barley straw extract https://amzn.to/2WXNO7u

Rigid insulation for building your own island: https://amzn.to/2LSXkmf

Coconut fiber for stuffing into holes in the insulation (great wicking capacity): https://amzn.to/2yszfzD