I have some strange spots that have appeared in my tank. I'm wondering if anyone can tell me what it is and how to stop it? Also some strange build-up that looks like calcium or sand but it's all along a corner vertically that is totally submerged. I am on well water and can't tell you anything other than it's hard, high in iron, sulfur and calcium i believe. Yes it's cloudy I was cleaning my algae off the walls.