PH 7.6, Chlorine around 3, on a regular basis, using Chlorine Tabs.

Water temp is about 90* (Arizona)

Run filter 10 hrs every night, sand filter

Pool water begins to turn cloudy, then green... we shock it with 2 bags of shock plus, run the filter 24/7, it clears up, then about 1 week later, it starts the cycle all over again, gets cloudy, we shock, yada, yada, yada.

Any ideas on why this keeps happening?

All tips/advice are appreciated.