Yabbadoo wrote:

WHY ?
Economics - saving is insignificant. pennies.

You never know. Some of us don't have electricity to spare. In any case,
we need to be encouraging people to save all the pennies they can,
electrically.

If you must - why not just use a timer (on 6 hours, off 6 hours)? better
yet - 2 hours on/off sequence to avoid possibility of filter stagnation in
summer months heat?

Many people would want the sound of moving water all day, but many outdoor
timers can be set to keep it on during the daylight hours, then run it 50%
of the nighttime, so that's a good (and cheap) solution.
--
derek