Sand filter allowing bugs to enter pool

[nicole12]

I had a thread a while back about my sand filter allowing fine dust into the pool. I've been dealing with it all season basically by putting panty hose on the return. It's taken me most of the season to try to get a new spider gasket for the pool and I still won't have it for another few weeks. At that point the pool will be closed so it will be installed next year.

This past week the pool was loaded with little flies/gnats on the surface. I had taken off my skimmer sock to clean it out and forgot to put it back on. That next day the panty hose was loaded with all the little bugs. It seems that my filter is letting out what "floats". The panty hose on the return will be filled with the dust and bugs, small leaves. Would that be a classic sign of a bad spider gasket? I just can't visualize how those bugs (some pretty big), leaves, etc can get past the gasket. I've looked at the gasket it has some questionable spots but overall looks good. I'm replacing it anyway but if there is something else that should be replaced over the winter (besides the whole stupid filter ) I would like to do that.

The other theory is that there is a gap in the lateral pipe and the selector valve, would that make more sense than the spider gasket?