well, the pump i bought came with a leaf trap, pressurized. that's probably enough really. Like I say, I'm just going to keep the pond vaccumed and at the end of the season I'll pull the top off the bead filter and see how much stuff didn't wash out with the regular backwashing. if it's a lot i'll revisit the prefilter idea. otherwise, i think it's just a solution in search of a problem.
got everything hooked up today, except the UV. Need one more fernco. I'll vaccum the pond and fire up the pump. I'll take some pictures too. The little pump house turned out kinda neat.