Thanks for the suggestion of vacuuming to waste. I do plan on it but I was trying to avoid it due to the water loss. I will need to be quick about it.

I opened the multiport valve yesterday and the spider gasket looks to be fully operational. It wasn't bent or out of the track. It looked rather new.

I guess the next step is to open the filter and take a look at the grids. I don't want to put more DE in the skimmer only to have to blow out the returns. Thoughts?