I have a rectangular above ground pool 16 by 24 feet by 4 feet deep. I live in New Hampshire. I have the ability to set the timer for the sand filter to go on and off twice a day. What time would be best to set it for, and for how many total hours per day should the sand filter run?

I saw a Pool that turned green supposedly because timer was am/pm reversed,
I think sand filter may be for circulation also.

I have an in ground pool with a DE filter, so my experience may not exactly correlate to yours, but I have found that running the filter 8 hours/day during the day works well. When I first start the pool up in late spring I run it continuously until the chemicals are properly balanced. After the first few days 8 hours/day is fine, and I always run it during the day as that is when the pool is most likely to be used.

I sincerely doubt that a pool turning green would be because of AM/PM reversal of the timer. The chemistry of the water, or failure to run the filter at all would have been the culprit.

That is what pool company told customer, It was circulating at night.
If your circulation was during day. You probably never experienced problem.
I have heard many Stories told to customers. This green thing, I never proved out.
Thanks, Ebaines

Run your pool circulation a minimum of 12 hours per day to ensure proper cleaning of your water. You can actually calculate the turnover rate of your pool given the volume of water as well as the GPH (gallons per hour) that your pool pump circulates. Unless you are an engineer with too much time on your hands, you would benefit from using the short cut estimate of 12 hours on and 12 hours off. In terms of AM and PM, I would run the filtration during the day and let it rest overnight with a solar blanket over it to reduce and chemical evaporation.

I hope this information is helpful.

Steve Goodale
Serendipity Pools