Sometimes you will have your multiport set in 'filter' and it will still be leaking water out of the bakwash. When this happens, something inside the multiport isn't fully sealing. There is a spider gasket underneath the keystem (handled portion of the multiport), that usually needs to be replaced. If it gets moved or crimped it won't seal and it will leak. Turn off the pump, unscrew the keystem and you'll see the spider gasket. Sometimes they are glued in and you'll need to scrape out the old one with a flat blade screw driver or something similar. When installing the new gasket the flat side goes DOWN and the ribbed side goes UP. You can apply a couple drops of adhesive to the bottom of the gasket as well to help it stay in place. Don't overdo it with glue though! If the spider gasket doesn't do the trick we also need to look at the keystem. Look at the tension in the spring. If the handle doesn't bounce back after pressing it down, the spring probably needs to be replaced in order to get a solid seal. We can repair or replace the keystems here in the store if you bring it in!