Hi! I am having a prob with water in my tanks looking dirty. It has a murky quality to it. I did change the filters a week ago but only because of the water quality. There are a lot of diatoms in one tank and I scrubbed the decor today. Love some help. please! Ph is 7.6, nitrites/ammonia are 0. Do not have a kit to check the ntirates. Both tanks have been up and running fully cycled and filled with fish since Feb, 06.