sump tank filter question

Hi guys, can you please comment on my sump filter tank setup ? It seems I have thrown in everything but the main tank's water is not that crystal clear. I do not know what else to add to my sump tank to make the water clearer and free from some small sediments ... my nitrates is a little high at 40ppm while ammonia and nitrites is at 0.







1st chamber is white filter wool, 2nd chamber is jap mats , 3rd chamber is jap mats and bio balls, 4th chamber is ceramic rings and floor polish pads .

Tks guys ...

Ok many tks ian and js ! I am using sera filter wool. I remember that because the sera filter is so dense the water flowed on top of the divider and didnt go through the wool anymore so I placed the wool more loosely in the chamber. Will try again placing the wool flat and see if the water is passing thru it properly now or maybe buy a different brand filter wool

Ok tks for the great idea ian ! Will look for those filter socks and will probably get those filter sheets - costs cheaper too