How many GPM does my pump flow? (look at these figures)

Turbota

Active member
Jan 14, 2013
42
SW Florida
I am just trying to ball park about how much flow that my pool pump puts out.
_________________________________

This is what I know:

1. Pump Motor: 1 HP (single speed)

2. Minimum Pipe Diameter in System: 1.5"

3. Operating Pressure at Filter: 25 psi

Note: Pool Capacity is 9,000 Gal. and the Cartridge Filter size is 100 Sq Ft.

I am thinking that the flow should be about 3,300 GPH (55 GPM) through the system.

Since my in-ground pool has a water capacity of 9,000 Gal, the water turnover time should be approx 2.7 Hrs.


Does this sound about right?

Thank's
Ron
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
13,505
Pleasanton, CA
That is probably close but it depends on the pump model. Not all 1 HP pumps are the same.

But I wouldn't be too concerned about turnover as it really has little to do with keeping your pool clean. Some pools need on 2 hrs of run time and some need 12 hrs. The factors go way beyond turnover.
 

Turbota

Active member
Jan 14, 2013
42
SW Florida
mas985 ... Thank's for the input :)

Since this pool was installed when the house was new (9 years ago), it was way before I ever owned it, so I had no input on the pump motor size that was installed.

But, for an in-ground gunite pool of just 9,000 gal, I think a 3/4 HP pump motor would have been just fine (I think that 1.0 HP motor that's in the system now is overkill, and costing me electricity dollars)

Also, the 100 Sq Ft. cartridge style filter that's on it now I believe is really too big ... For a 9,000 gal pool, I am betting that a filter of 75 Sq Ft. would be better suited for the pool (I need to buy a new filter assembly anyway).

Ron,
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
13,505
Pleasanton, CA
A simple and cheap fix is to just downsize the impeller. But if you really want to save money on energy, you need a two speed motor as well. Running on low speed saves far more than just downsizing the pump.
 

scooperhsd

Well-known member
May 10, 2009
395
Youngsville NC
There is no such thing as a pool filter that is too big. In fact, the general guidance here is to get as large a filter as you can afford / squeeze into the space, especially if you have a cartridge type filter. It will clean better for longer time in between cleanings.

If you're looking to reduce your pump running expense - often, you do not need to run your pump 24 hours /day. So, you start by cutting the time that you run the pump (using a timer) a bit at a time until it isn't staying as clean as you like, then add abit more time until you get back to where you want. Using this, I've determined that I need to run my pump about 9-10 hours per day after my initial cleanup from opening the pool.

After this relatively simple thing, you can look at the other things that have been suggested - smaller impeller on the pump, replace it with a 2 speed motor/pump, etc.
 

Turbota

Active member
Jan 14, 2013
42
SW Florida
Well, right now I am running the pump 5 hours a day here in Florida, and 7 hours a day during the summer.

Again it's only a 9,000 gal pool, and it does stay very clean.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
13,505
Pleasanton, CA
I have a 20k gallon pool with a 1/2 HP pump (0.5 HP) and run the pump about 4 hours per day during the summer (two on high speed and two on low speed) and 2 hours/day during the winter. So you could very well get away with a shorter run time if you just try it.
 

Turbota

Active member
Jan 14, 2013
42
SW Florida
scooperhsd said:
There is no such thing as a pool filter that is too big.

In fact, the general guidance here is to get as large a filter as you can afford / squeeze into the space, especially if you have a cartridge type filter. It will clean better for longer time in between cleanings.
Thank's ... I will buy the Pentair CC100 (100 sq ft) filter instead of the smaller Pentair CC75 (75 sq ft) filter that will replace the Hayward that is in the sytem now, that I can't get apart anymore to wash out the filter element (warped housing).
 

linen

TFP Expert
LifeTime Supporter
Jul 30, 2010
8,649
Twin Cities, MN
Turbota said:
I will buy the Pentair CC100 (100 sq ft) filter instead of the smaller Pentair CC75 (75 sq ft) filter that will replace the Hayward that is in the sytem now, that I can't get apart anymore to wash out the filter element (warped housing).
Although you can probably get by with a smaller filter, our recommendation for your 9000 gallon pool would be a minimum 140 sq. ft. cartridge filter (as scoop mentioned above, a cartridge filter larger than that is not a problem). That will reduce how often you will have to clean it.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
13,505
Pleasanton, CA
Two speed pumps also benefit from the pump affinity laws. But VS pumps rarely have a lower lifetime cost than a two speed. Only expensive electricity markets with VS rebates combined with a larger pool see a benefit over a two speed.
 

Bama Rambler

Mod Squad
TFP Expert
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Jun 22, 2009
24,021
SouthWest Alabama
A VS pump on a 9,000 gallon pool without any special water features and in a area that doesn't have high electric costs is way overkill, the best bet would be to just replace the existing motor with a 2-speed. Even before suggesting that I'd try Mark's suggestion of trimming the run time, and replacing the motor once the existing one started having problems.
 

Turbota

Active member
Jan 14, 2013
42
SW Florida
"A VS pump on a 9,000 gallon pool without any special water features and in a area that doesn't have high electric costs is way overkill.

Best bet would be to just replace the existing motor with a 2-speed.

Even before suggesting that I'd try Mark's suggestion of trimming the run time, and replacing the motor once the existing one started having problems".

____________________________________________

Thank's

That's exactly what I am going to do ... trim down the run time a little first and see how that works out ... and when the 1 HP motor that I now have finally fails, I might replace it with a smaller 3/4 HP motor (again, I think that the 1 HP motor in my system is really too large since the pool is only 9,000 gal).
 

ShowtimepoolsAZ

In The Industry
Mar 11, 2013
9
Arizona
Look at the pool time clock study done by Florida Atlantic University. If you put a 3/4hp motor on your existing 1hp pump, the new motor will overheat and fail. I would recommend a 1hp 2 speed pump to allow for storms, cleaner wear, and a dirty filter.
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
43,238
Tucson, AZ
ShowtimepoolsAZ said:
Look at the pool time clock study done by Florida Atlantic University. If you put a 3/4hp motor on your existing 1hp pump, the new motor will overheat and fail.
... unless you also replace the impeller.

But, you have to check the HP and the Service Factor as a 3/4HP full-rated motor could be equivalent to a 1HP up-rated motor.