Death at the Pool

We purchased a pool last year, it is quite small. It's one of those pools that you blow up the top and as it fills the top raises. I'm not very good with measurements so I couldn't tell you how big it actually is for the life of me, however I am 5'1" and it comes just above my knees...so you have kind of a picture of the size of this pool.
I also have 2 children and they have friends, friends who enjoy spending time in our pool. Well the very first time the pool was used this year was by my daughter and her best friend. They were in the water for around 3 hours, and my daughter had come in the house to use the pool around 5 times in the duration of the 3 hours. However it hit me that her best friend had not come in once, so as I am telling the girls to get out of the pool I ask said friend if she had been peeing in the pool. She responded with a look of guilt and silence. Therefore I was then planning on draining and cleaning out the pool because that is disgusting!
I didn't get around to actually draining the pool out until a couple days later and as I am preparing to do so, I see an animal floating in the water. Apparently a squirrel had fallen out of our gigantic walnut tree to him ultimate demise, or he was trying to get a drink and fell in, either way he did not make it out again. I am not sure if he fell and was stunned then drown, or if the chemicals from this little girls urine killed this poor squirrel. I am however going to use it as a reason why you should not pee in the pool!