It's not quite clear to me whether you're asking what you can do to keep the frogs out of your pool or from displacing native frogs, but I don't think there's much more you can do either way. At the smaller scale, as long as your pool has water in it, they're likely to use it. No doubt you don't want your pool full of frog eggs and tadpoles, but if you didn't clean the eggs out the tadpoles would starve to death if the chemicals didn't kill them or the eggs first. At the larger scale, it's extremely hard to get rid of invasive species once they're established. In a general sense, the problem of invasive species is one of the greatest threats facing our wildlife, along with habitat loss, climate change, and pollution. Support any government or private programs to control these species in your area.