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Part of the maturation process. I shorter or bluer light cycle will slow it up a little but don’t fight it too hard. Green stuff is next. Then some furry brown stuff. Some rust stuff on the sand. All good things that are trading the balance of power over the first 12 months.
Like the above said, don't fight it, algae is coming and there isn't much you can do about it. The faster and harder it comes at you the faster it will go away. Natural process.