If your "particles" are detritus or residue from rock/sand, then you will need a filter with the capability to strain out very fine particles. The tidepool is a great system, I have it on my 75 gal, but when I do a water change, I add an aquaclear powerhead with a filter attachment which removes ALL cloudiness or fine stuff floating around in the water.
If your 'particles' are moving on their own, then you may be seeing minute creatures that live in your tank. Turn off the filters and watch closely to see if they are moving around. I have noticed at night under the moonlights on my tank, there are tiny critters swimming around My PJ Cardinal swims around eating whatever he can catch.
