I have to add some new aragonite sand to my existing sand bed. There is some GHA on the top of the old sand bed. Is it ok to just put the new sand on top of the old sand and green hair algae?
You should remove the hair algae. Otherwise it will die under the new sand, and you will have the decaying matter trapped under your sand, that;s not good for water quality!
If it is growing on the sand, you should be able to just peel up the algae in a clump.
