Seniors always awnswer..can u help?

i had asked this question on answers with no results so maybe a senior might be able to help. i recently bought a plastic kiddie pool-the type you have to inflate. it is good size.330 gallons. i want to keep the water as fresh as possible..don't want a dark black lagoon looking pool. i don't want to change the water daily. i bought this pool for my elderly mother so she can cool off in the pool on a hot dayand get a little sun. does any senior have grand kids with kiddie pools or remember how they are maintained . was this consistently new water?.