So, uncle Salty, I am very sad to tell you I suspect you won the battle but may be in for a war
I say this as someone who lives across the road from a bee keeper. Bees will truly PREFER your water source, especially with salt. Chlorine is like alcohol to them. My bee neighbors have the entire Grand River at their disposal and yet they come in hoards. And I have borates at 50 ppm.
I have literally begged the bee keeper to mist them in dry spells to prevent them from foraging for water etc. but he doesn't get the nature of the problem (or get that as someone with an allergic sib why I am opposed to sharing the pool.)
I have consulted with more conscientious beekeepers on this and even talked to an entomologist so I'm happy to share what I've learned.
Since I am unwilling to risk poisoning the hives by using Tempo, I too have a Dawn Death tank at my disposal. But I also have some other tips that might help cut down on the discovery of the pool and the number of summer days you spend toting around te Dawn of Death as we call it
1. I'm assuming you've determined that they're honey bees...be certain about this part because if they're sweat or carpenter bees there are completely different approaches and with wasps, some of this would be downright dangerous
Bees are social and signal distress but unless Africanized will not be aggressive with you.
2. The next time a bee shows up, bee line it, meaning at dawn and dusk, observe the direction of flight And try to triangulate it. There is the chance that using bee lining tricks you a discover a feral hive which you could then convince a local beekeeper to possibly relocate and domesticate. Given that you had hundreds, this is my suspicion in your case.
Here's an article on how to bee line to find a feral hive...
Bee Lining: The Oldtimers Way to Find Wild Beehives | Summer 2010
3. Conceal bright colored pool noodles when not in use. Bees don't actually like open water...they far prefer sucking chlorine from wet spongy things. I now keep a tall cabinet and deck box that all pool toys go into immediately after use.
4. Once you know the general direction of descent, place that bird bath somewhere in the path before the bees can see/smell your pool. Fill it with saltwater from the pool, put a bright sponge in the center, and top up the salty chlorine water daily. You will deceive some this way if you are vigilant.
5. This sounds crazy and came from the entomologist, but a show of extreme violence early on with initial scouts CAN help word get back to the hive that you are hostile territory. We call my husband "Bam Bam" given his ritualistic bee-bashing-with-pool-noodle routine he's developed with theatrical flair. If not too drunk (chlorine really does make the bees drunk) the odd survivor of the death dance will phone home. Be sure to leave a survivor for this purpose.
6. Lastly, since I know personally how much it sucks to have to kill bees, I want you to know that there's a good chance many who show up to your pool are on their last days anyway. Prior to death, bees wander off from the hive to forage for water. Many of these guys are retired and literally are out for a last hurrah. So it might help to consider you are giving them a soldiers death
At least, that's what I tell myself...
I hope you are able to locate your hive before late summer and are able to find a beekeeper to relocate it. I had no idea I had a bee keeper across the road until I beelined it. In my case, the news wasn't great, because he's old school and feels the bees know best and that "we all need to share" my pool. In your case, based on the numbers, I believe you may have a hive nearby, possibly feral, so will need to remain vigilant.
