This has only happened a few times over the last 15 years. When I pull my filter for cleaning, I clean my filters every month, the main filter is plugged with hard tan scum. In the spa itself there is some, not a lot, of what looks like strings of white jelly floating. The water is crystal clear and the CL level was a little low but not bad. See attached photo of main filter and aux filter. The aux filter is fine. Does anyone have any ideas on why this happens?Plugged Tub Filter.pdf