You can feed some of the algae to the fish. Removing it and selling it or throwing it out, removes waste that was assimilated into the plant. It is good for your fish to eat, but if you feed it all back to the fish they will put this waste back into the system. I keep the refugium lights on 24/7 so it will produce oxygen day and night. Plants use oxygen and produce co2 when the lights are out, also some calerpa will release a substance at night that can yellow your water. This is why itââ"šÂ¬Ã¢"žÂ¢s a good idea to run your lights 24/7. I use Calerpa Srtularioides in my refugium.