Hi, just looking for some suggestions. 20 gallon Red Sea max nano with protein skimmer and AI prime LED light. Tank is about a year old. Every time I turn the light back on after killing off whatever type of algae starts growing on the rock within a few days again. I’m using RO water, Red Sea coral pro salt and I’ve been doing 5 gallon water changes at least once a week and maybe even twice a week to try to prevent this from happening. Any thoughts?