I just bought and installed a Hayward S244T sand filter and noticed after a few days of operation that is water accumulating around the filter support stand and under the filter. It turns out that water is leaking from the drain cap. No matter how tight the cap is, water continues to leak. There is an orange/red gasket inside the cap but it does not seem to do it’s work properly. Do I need to add silicone in there? The thread is not continuous so Teflon tape will be useless. Is this a design flaw?