Hi, I constructed a small pond a last summer about 100l x 90w (rectangular), and with depth at about 9 feet deepest. The water was muddy then I added some hay which cleared it up. But the pond hasn't stayed the depth I set out for(it should be 8 feet then 12 feet,with a small area of 3) which no it is 2 1/2 feet at one end and 6 at the deepest. I have catfish and bluegill and I notice after a rain the water is as clear as can be but if doesn't rain for awhile it becomes muddy. I've never used fertilzer or anything other than the hay and some lime. The fish sometimes look pale but other times they are good, they are still feeding and agressive, growing too. Should I use sulfate or gypsum, I hear alot of talk about the 2 but i'm just looking for the easiest way to find either of them. Also, after the water clears should I fertilize? i'm just learning as I go.