I saw this, and I thought huh, should be simple to make. And might be perfect for aquaponics as the less algae in the tank, the more food for the plants....
Just passing this idea along... We probably could grow / make this...
If you manage to kill off algae in a media bed system by shading the tank heavily, and let the dead algae decompose in the media bed, it will give off much the same chemicals that barley straw does and will help to inhibit future algae blooms and you don't have to keep buying a product to do it.