55 gal tk w/ live rock live sand protein skimmer & 401 fluval canister filter, only 80 watt lighting. I've had the marine tk running for about 3 mos. w/ three fish 2 bicolor damsels & 1 green chromis, lots of turbo snails & blue legged hermit crabs. there is a 2 in diameter maroon patch on the live sand that seems to intensify w/ light. Also wed like sticky tenticles that come from the live rock. Any idea??