How long to run pump & at what speed?

[mas985]

I thought that the conversion was 2.3 feet of water per PSI so that you would multiply PSI by 2.3 to get head loss in feet. Am I missing something?

Richard

2.31 times the filter PSI will give you only the return head loss from the filter to the pool. Head loss consists of both return and suction losses. The most accurate way to measure suction loss is with a suction guage at the pump. Unfortunately, most people do not have one nor willing to buy one so I usually skip that suggestion. So without a suction guage, a pretty good estimate for suction loss is 30% above the return head loss which results in a factor of about 3 (2.31*1.3 ~ 3). It gives an answer with a little more accuracy than 45-65 feet of head.

BTW if you do have a suction guage, then multiply inches of mercury by 1.13 to get the suction head.

[chem geek]

Thanks Mark. I figured it was something simple I was overlooking. I really appreciate your clear explanation.

Richard

[tphaggerty]

I would add that you might want to consider breaking up your run time into 2 or more increments, especially if you are running for less than 12 hours a day. Of course, you need a pump timer to do this.

I just find that my pool seems to stay cleaner and the SWG seems to work better if I add a 2 to 3 hour night time run to the 10 hours or so I run during the day (we run during the day due to solar heating). Stuff has less opportunity to sink and it just makes me feel better to know that I am not leaving the pool completely stagnant for 14 hours straight.

[ePoolUser]

Could someone put this formula into layman's terms? I don't see where head loss fits into the formula..
>>First you need to determine head loss. In most pools that is between 45-65 ft on high speed ...
Then determine your turnover rate. Turnover (hours) = Pool Volume / GPM / 60<<

Where is head loss used in the equation?

Obviously I'm missing something (brains?).

TIA,
Steve

[mas985]

Could someone put this formula into layman's terms? I don't see where head loss fits into the formula..
>>First you need to determine head loss. In most pools that is between 45-65 ft on high speed ...
Then determine your turnover rate. Turnover (hours) = Pool Volume / GPM / 60<<

Where is head loss used in the equation?

Obviously I'm missing something (brains?).

TIA,
Steve

Here is what I had posted regarding converting head loss to GPM:

Next look up the flow (GPM) on the pump head curve for both high and low speeds. Low speed should be 1/2 of high speed GPM. Low speed head loss should be 1/4 of high speed.

Usually, the pump head curve is in your pump manual. The vertical axis is head loss and the horizontal is GPM.