The tank was atrocious, the water looked like milk, the tank had white skum all around the sides. I came home and changed the water and have it filling back up as we speak, but I will tell you one thing, I have the cleanest sand that 125g of RO water will clean. It took me three hours to take the water out and wipe everything down. When I put the sand in, I put in two fourty pound bags of dry sand and one twenty pound bag of live sand. Will the sand be alright ? I am sure I will have to replace the twenty pounds of live sand, is that right? Anyway the tank is clean and the water is going back in clean. Lesson Learned