Pool X: Wohooooo the Polaris is working well. I am going to have to add a small modification though. The pool water itself has gone completely non-toxic and my little test critters are now starting to do just fine. 
Now I’ll be able to start adding plants and more complex critters.
Pool Y: I have now started this one and the water unfortunately is still too toxic for some natives.
I will comment again that: an owner comes out to find a little chorus frog or a slender salamander floating in the pool and they say awwww the poor thing, it drowned. And I cringe, and think, it didn’t drown it’s an _aquatic_ animal. They are poisoned by the chlorine. And the chlorine in this pool is entirely municipal (drinking water). People that own aquariums have known for many years that you can’t just fill up an aquarium and put fish in because the water is too toxic. And you are _drinking_ it. 😜 
This particular pool is collecting rainwater from the roof and they were able to collect a fair amount of water with the last rains.