Valve between pump and filter.

[swimdaddy]

That is interesting that the pump actually uses less energy and runs cooler with restricted flow. I do find that the filter, for what it is worth, does a better job with less flow. Its an intersting game I play, dropping the PSI with the control valve and then raising it some with DE. I think I learned this year that I probably backwash too much. I got in the habit of backwashing once a week but if the pool looks good and the PSI hasn't risen there is probably no reason to do it.

I have abandoned the idea of the rheostat or step down transformer, sounded good though.

The valve works really well, small movements change the PSI a lot, very fine control. Is there an ideal PSI to shoot for for efficient filtering? I don't know what my flow rate is, but the return jet is strong, kids can use a noodle to shoot water a good 15 feet. At fully open, 16psi, with DE 17psi, I have been throttling that down to 10 or 12psi.

[CarlD]

Mark knows more about pumps than I do, so his advice takes precedence over mine.

We've well-documented over the years what you have found: A sand filter filters better with less flow. Something about the dirt not being forced past the sand as easily. That's why I'd rather run it on Low (2spd pump) than High pretty much all the time. Thus a bigger sand filter does better for the same reason: More capacity for the same flow.