I dose coral snow too. Brushing doesn’t do much for the GHA I have because it’s too dense.Thanks for the feedback, I think my situation would be worst if I didn't take the time to clean by brushing and siphoning the gha I have. It almost being done almost every 7 to 10 day at a time. Also I'm dosing fiy coral snow after blowing the rocks weekly. Just trying to keep the junk of the rock to feed gha.