I don't believe my tank is overstocked, the main thing in my tank is the cleaning crew. I have about 15 turbo snails, 3 conchs, 2 urchins, 1 sand sifter, 6 blue leg crabs, 1 sally lightfoot, 1 emerald crab, 1 yellow tang, 1 neon blue damsel, 1 firefish, 1 coral beauty and 1 blue hippo. It's a 75 gallon tank with lots of live rock. And also right now lots of alge, I am pretty sure that the water is the problem. The phosphates are wacky up and down, zero one day then the next day there is a reading. Currently, I am topping the water evaporation with distilled water and going to the local fish store for some water for a water change. Hopefully this will get the water phosphates in controll. I was just wondering if I would have to actually scrub all the rock or buy new rock (which I don't want to do) to get all the alge off. Any suggestions, it would be greatly appreciated. Thanks in advance.