sand cleaner suggestions

[neotekz]

i have 9 blue leg hermits, scarlet hermit, 5 turbo snails, and 8 other assorted snails, a emerald crab and a pepermint shrimp, and a tiger cuecumber. i'm using tap water(probably part of the problem) which is all i can afford right now. water has no ammonia and nitrites, nitrate is about 5-10.
it's the red algae on the sand that i want to get rid of, the rock has some hair algae but the crabs are working on that. some of the hermits are cleaning the sand a bit but not faster than the algae can grow. i got 2 powerheads and turn about 20 times the water. so what can i do until i get a ro/di unit to reduce the red algae?