When my pump is off my multi-port valve makes noise and the pump basket loses water over time. Last year I replaced the spider gasket because it was leaking a lot of water out the backwash port. Now it is still leaking (a drip at a time) enough to cause my pump basket to lose water. When I plug the backwash port with a rubber stopper the pump basket remains full. Since I replaced the spider gasket last year how should I address the leak in the multi-port valve to prevent my pump basket from losing water?