I've got a Hayward S270 (top multiport SP0714T) with a Hayward Super II Pump (1.5 hp) that I've used together since 2009. Swapped out the original zeobrite for sand, and then last year swapped out the sand for Dryden Activate glass filter media (which I am very happy with). No problems using through end of year last year, including the occasional backwash. Opened the pool yesterday with no changes from last year other than winterizing as every year. This year, first time I backwashed, started losing a lot of filter media - like 1 to 2 cups per minute. backwashed for a few minutes and rate of loss never slowed down. I'm not losing any media in rinse (discharge into a 12 gal bucket). Not seeing any leaking to the backwash hose when filtering or recirculating. Pulled the multiport off and the visible part of the standpipe looks fine and the multiport is seated on it fine. Inside the multiport looks fine - body is not split, spider gasket appears to be good. Only change from last year is that the filter sat dry/drained for the winter. Anyone got any ideas?