Pool Attracting Flies

[Bob in Ozarks]

We have that problem this year (2017) for the first time. The pool was opened, but still too cold to swim and then literally thousands of black flies with small wings and fat bodies were covering the pool surface. I think the algicide I used this year (different brand) attracts them and it kills the surface tension of the water, so when the fly lands, he sinks a bit, gets wet and then can't fly away. We have skimmed our pool every day and every day we have a skimmer basket full of dead flies and hundreds more on the surface. Sort of like a plague.
On the good news, we had no flies hovering around the grill when we were cooking.