GHA in overflow

[BlueAbyss]

Any algae that grows fast and is harvested regularly will act as nutrient export... the key is the 'export' part. I would scrape some off regularly, collecting (and removing) the scraped algae... couldn't hurt. Sort of like an in-tank algae scrubber.

Having GHA in your overflow probably doesn't hurt anything if it isn't taking over your tank (or plugging the drain).