Not all al-gae - not to be confused with Al gore (tho they seem to work at the same intellectual level) - are useful for human food tho.
DO you know what kind you have growing?
I wasn’t necessarily thinking of food as a use. As for types of algae, they are numerous. The most common in small ponds/water gardens is string a.k.a. “hair” algae.
I should clarify about using the algae. Algae is of course, cellulose. I was thinking more along the lines of fabrics and papers (non-woven materials).