Having problems looking after brine shrimp!!?

i got them in an 3 gallon tank and i got a filter with stockings over it so it don't suck them in. it gets clogged up every 3 days and at the bottom of the tank its some fluffy gewwy crap! lol i dont know if they feed on it because its week 2 weeks since i haven't fed them. i dont no what that fluffy stuff is it looks slimy. how do i maintain aeration because when i put air-stone in it they go every where