Do you use a solar cover? What do you keep your fc at and what is your cya?
Agreed nothing keeps them out, but as a person who has had more than my fair share of bug problems, I found keeping my fc around 11 for a cya of 45 tends to keep most of them away. When my fc dropped to 5 I had a ton of them. I just know when the chemistry is getting off when we are outnumbered by uninvited "guests". YUCK!
Keeping the cover on until just before swimming, and not using a light at night has also helped. When we light the pool we get bombarded with them at night.