I guess I don't know what you are filtering out.
Here, our water is so high in PH that, without some exposure to the sun, the filter will only plug up with all those beneficial bacteria. Lowering the PH helps some, but the run-off from rain puts you right back where you were. Lower PH also helps to control the algae colonies in our filtration systems, which are another consequence of sunlight exposure.
Your water looks pretty clear to me.
Of course it looks clear; it's got a filter in it.
That tank was only set up about a week ago, so it's not had time to develop many problems, though there was some particulate matter accumulating in the water from food scraps and exoskeleton shedding, which was filtered out very quickly when I stuck the filter on a couple of hours ago. I have an older tank that was quite dirty with particulates, and it's much clearer now too, though the water is a bit brown from tannins that leach out of leaf litter that my invertebrates feed on, and the plastic has gotten a bit stained from the tannins. The pond's problem is free-living algae which have turned it a murky green, and the best way to deal with that is to reduce the nitrates in the water through denitrifying bacteria in the filter medium that will consume the nitrates for energy and break them down into nitrogen and other inert substances. We got some goldfish for the pond today too, so they'll add to the nitrate load.
