Sorry it took so long to get back to you.

1. Any time you have algae, your filter & pump should be running 24/7.

2. As a general rule, AG sand filters are UNDERSIZED and mated with pumps that are OVERSIZED. Why? At sales time, pump HP is 'sexy' and filter inches are not!
Oversize filters drive dirt THROUGH sand filters and WASH SAND OUT during backwash. Most AG pool sand filters are 1/2 empty of sand after a year or so of operation. You can test it: http://pool9.net/de-test/

3. Letting a pool operate in a state of 'almost green' wastes chemicals, wastes electricity, and wastes time. It is MUCH easier and cheaper to run an algae-free pool BUT you have clean it up completely first. AND, you may have to REPAIR your filter.

4. Controlling algae takes more chlorine than common test kits can measure. Buy a K2006 on Amazon, test pH, chlorine AND CYA (stabilizer) levels. Then, run your chlorine level at 1/4 of your stabilizer level for a WEEK.