Ugh. Summer 2 with the pool and still cleaning it every week or so.
Going to try this next.
http://www.backyardkid.com/home/2018/5/7/how-to-keep-the-kiddie-pool-water-clean-all-summer-long
June Update
Raise the alkaline level of your pool. Baking soda is the best stuff in the world for this. Sodium Bicarbonate.
https://www.poolandpatiopros.com/how-to-raise-alkalinity-in-pool/
This one tries to enable push notifications, remember to block.
https://home.howstuffworks.com/swimming-pool6.htm