We want to help you keep the pool 'in control' while you learn more. So, right now, go get a cheap OTO/phenol red drops testkit, and 16 gallons of PLAIN 8% household bleach from Walmart. Also get the HTH 6-way drops kit, if available.

As soon as you have the bleach, add 2 gallons that EVENING. The next evening, test with one or both kits, report results and water appearance, and add another gallon. It's MUCH easier and cheaper to avoid algae, than to clean it up!

. . . and order the K2006.

. . . membership upgraded.