So… I went out of town last weekend came back and the water was all green and sand was all brown never seen it before everything was fine have 2 clown fish and 4 coral…. Well when I came back I found that one of my snails had died and also my torch coral polyps started falling and knew there was no saving it so I disposed it of it. I cleaned my tank did a big water change, tried to filter/ turn the sand over. It kinda look good but I decided to change the carbon back and filter floss also added some more bio media and added some fritz aquarium cleaner but it still looks cloudy. I tested my water parameters and everything looks fine except my alk is high (10.9). I don’t really know what step I should take cuz I seen a lot of stuff to do, should I buy a UV sterilizer as I heard it was really good. Also what do I do with my sand bed getting dirty quickly.