What could be done to remove food particles (as sm said in a previous topic) from the display if I'm running an ATS?

Also, why do some people say I need to run a skimmer along with an ATS?

Maybe I answered my own first question. But I do notice that my 175g, while op'd solely on a skimmer, is crystal clear. And my 90g(ATS) is murky, to say the least.

Is calc dosing necessary with the ATS?