Front every couple days. The left side Ive done once. The right side I’ll do it every week. Back, I just blow the top part off with the turkey baster cause I can’t reach any lower, but I only do that because I get a cyano like film over the diatoms, that flakes off and the blenny won’t touch
Cyano is toxic to a lot of things, the algae it needs is under it, are you fighting the cyano?