Can you supplement with algae wafers?
You'd have to crush whatever you want to feed them to a powder or as close. I have a mortar and pestle which I used to crush flakes and pellets. I haven't tried with algae waters I used high protein flakes made from worms but I haven't had success with supplement feeding. Initially, they didn't seem feed on it so you definitely need live algae growing and present in the water for them to survive.