Sediment at bottom of res.. Help!

I'm using advanced 3part grow-micro-bloom base nutrients..

After a handful of days, you can see what looks like dirt at the bottom of my res.. Assuming this is salt deposits, what can I do about it?

I have an airstone in there, and a return line that drops water into it as well.. So why am I getting these deposits?

Is it definetly nutes causing buildup or dust from mediuum? I am currently using 100% perlite and get light dust build up in bottom of res, if thts it i wouldnt worry unless you got drippers with tiny tiny holes?

Well the medium is hydroton in netpots but its already been washed well. I think its nutes because there's slimy little things floating around the top too.. Any other thoughts on how to fix the issue?