Original problem was filter sand coming into the pool via returns. Took apart filter, checked the lateral, no cracks. Reassembled and restarted, still sand coing in from the filter. Took apart the VariFlo XL valve and saw the spider gasket was chewed up, so ordered a key/seal assembly with a gasket. Question-when it arrives, can I just pop it in the Vari-FLo valve and start it up or do I need to take the sand filter apart again to clean out the sand from the folding lateral assembly? I'm also assuming I can vacuum up the sand still in the bottom of the pool back into the filter or is that a no-no? Many thanks for all the help!