Wow, I remembered posting this last year but I didn't realize I never answered the replies. I am embarrassed and apologize!
I went looking for the post because it is that time of year again and they are back in the same numbers.
JasonLion I will read further on borates - I assume you meant as used here as part of the water chemistry. I know there is a specific "advanced" topic on that somewhere.
woodyp I don't really want to kill them as I assume they would just be replaced fairly soon by a new hive. This is not a developed area, it is pretty much just nature and any void would likely soon be filled. heh
duraleigh I have not tried that, I am thinking about it. I do have three humming bird feeders out and they get a few bees, but I think they are after water (this is Arizona in June, our driest time of year). They tend to crowd around any source of moisture this time of year. We get a lot of wasps too. I don't remember them doing this with my first pool 10 years ago. I hesitate to add another attractant such as "food" - I am afraid instead of luring them away from the pool it would draw more of them.
Butterfly I am not sure where they are coming from, I am on a ranch with a lot of potential wild hives and a lot of distance from waters. They could be coming from miles away. Or however far they will travel. We used to have a hive in a tree nearby but they don't seem to be there any longer.
Anybody else have any experience with this or ideas?