Algae is a sign of an imbalance, not tank health. That happens to be what the OP is attempting to resolve.
Note: In some cases, algae is desirable an an imbalance is purposefully introduced. As is often the case with keepers of Stiphodon atropurpureus. They use purposefully super-strong lights to grow tons of algae, microorganisms, biofilm (aufwuchs) upon which Stiphodon primarily feed.