I don't mean to gross you out, but could you pull the filter pads/cartages out sooner and rinse them? It sounds like they are doing an excellent job (also) as mechanical filters. It might be better to remove the "big pieces" of food or whatever, which get caught upon them. The action of the water and the microbes in the tank will begin to break those larger items down (first into  some ammonia). That adds to the nutrient soup in the tank which could encourage that cloudiness.

In a certain sense I hate to make suggestions, because you are doing such a magnificent job of doing all of those things. I'm sure you have wondered if "no good deed should go unpunished."

An old buddy of mine called up yesterday and we spent a lot of time talking about some problems in their son's new fish tank. He did a lot of things right, moving in the gravel from a smaller tank, etc. His big mistake was the old classic of buying far too many new (unquarantined) fish and blowing up the capacity of the tank to cycle ammonia.

As we went over what had happened, I was reminded of an observation by my biology teacher that all sorts of things within an animal's system and within their larger environment are based upon equilibriums. By adding so many new fish to any aquarium, we really upset the equilibrium established by the fish and the beneficial bacterial cultures.

It is sort of like when we are ill and are prescribed some really powerful antibiotic. It "gets" the bacterial illness that is afflicting us, but also kills off most of the useful bacteria in our digestive systems, which enable us to digest food. Then we may have to deal with a horribly upset stomach and the banshee-two-step.

And after Christmas, when I look at the balance on a couple of charge cards, I wish there had been a better equilibrium between payments and expenditures. :(