Write a novel? I feel very guilty of doing that, so I will try to keep this short! The pre-filter gets clogged fast as it is the only thing keeping gunk from going through your pump. If your pump is small, or more important, if the line from your pump is small, then it cannot handle much gunk. Move it off of the bottom of your pond, if possible. That way it will still gather stuff that is free floating, and send it through your filter. Try this: Get a piece of floating insulation board. Put a small container on top of it, run your line into the small container (which should have holes in it to drain the water back into the pond) and put quilt batting in the container. That way you will have a much better filtration system temporarily and won't have to clean your pre-filter as often. I hate having to pull my pump. In fact, besides swishing the stuff off of my pumps when I'm in the ponds grooming the lilies, I have not pulled them since spring, unless I had to change the line or something. I have them on a milk crate. Not sure if that would make your pump too shallow, though. Even putting it on a flat rock would keep it off of the bottom. And, the filter system I described is very basic, but will do a load of good. Get a roll of the quilt batting, maybe $5 or so worth, and have a double or triple layer for the water to run through, and have a second pad ready when the first one is filled with gunk and not going through it any longer, you can swap them out. Then, as Sissy has told all of us to do, rinse out the first set, hang it out to dry (which will help kill any algae) and if you put it in a bucket of water with some peroxide in it, that will also help kill any algae cells. Then keep swapping them out with the one being used. Good luck!