I have an Intel pump with my sand filter. Got it last summer and at first it worked well. Towards the end of summer it began losing the vacuum in the pre-filter. It would draw air into the pre-filter and then lose suction. I'd let the air out, restart and it would be fine for awhile and then back to the same thing. I ended up closing the pool, planning to look at the pump during the winter and of course completely forgot about it until I opened it today. Same thing, only this time it also leaks water around the housing where the pre-filter fits onto the pump. I took it all apart, cleaned it, applied petroleum jelly to the O rings (which still look brand new) but it's still leaking and of course losing pressure as well. It's filtering some water but not doing very much and of course I can't vacuum at all.