Fyi, my FOWLR tank have no algae issue given all my saltmix water is using tap water with anti chlorine..my top up tank oso the same..top up ard 5L daily..
algae usually will strives under some requirement..
1. Lighting..I m using normal BW led light..maybe not strong enough..but my tank have some morning Sun though..
2. Flow..I find that with good flow, algae harder to grow..my tank have ard 18000lph turnover n 2 x wp40, providing very good flow..
3. Feeding..I dun overfeed my fish..on auto timer, 2 times a day (11am & 6pm)..drop pellets that fish can eat all within 3min..occasionally hand feed nori seaweed from ntuc or mysis & brine shrimp in between..
4. Luck..
Cheers n happy reefing..