Leaking valve!! Advice needed please!!

Hi from NC,just filled the pool and I have water running out the waste port of the valve on top of sand filter.It runs out when it is in the filter position.I think their may be a gasket that may need replacing,if any one has some advice or info I would greatly appreciate it! Thanks.

There is a gasket under the multiport handle that can be replaced, and if it's missing or installed incorrectly it will direct water where it's not supposed to go. The last gasket I bought ( a couple of weeks ago) cost $15.50 at my local mom 'n pop pool store, and it takes about 5 minutes to install.. There have also been incidents where the whole handle assembly has been replaced upside-down or turned slightly, that can result in crazy results. Those are the first two things I' would look at.....

Thanks! I will investigate!!!!!