Consider Turbo Snail and Tuxedo, they are algae eaters, since u already cycle ur tank with Rowaphos, i assume phosphate readings are low which deny algae growth. No algae = Turbo Snail and urchin gonna starve and die off which can lead to nutrient problem. I would skip the turbo snails and tux if u dont have an algae problem (btw this critters will end up on u glass wall instead of rocks). For rocks, get blue/red leg hermit.