If you have suspended solids in your water then you need more mechanical filtration.
Try 9 watts of UV light. It will make your tank very clear.
I use a powerhead with a prefilter on it to pump water through a 9 watt uv light on my 120 and I have a Green Killing Machine uv I think it's 9 watts also on my 125. Both are very clear. Soon I'll be hooking up 40 watts on my 500.