(Click on a star to add your rating)

**Click Here to View Inground Pool Pumps**

Your first step is to determine the number of gallons of water in your pool. The formulas for calculating the gallons depend on the shape of your pool.

For a RECTANGULAR POOL:

Measure the length (ft), the width (ft) and the average depth. The average depth is determined by adding the depth at the shallow end to the depth at the deep end and dividing by two.

The formula for calculating the total gallons in a rectangular pool is: Gallons = Length x Width x Average Depth x 7.5.

For example (see picture): your pool is 30 ft long and 15 ft wide. The pool's shallow end is 4 ft and its deep end is 8 ft. So, the pool's average depth is 4 plus 8 = 12 divided by 2. This gives you 6 ft. The pool's capacity is 30 ft x 15 ft x 6 ft x 7.5 = 20,250 gallons. Go to Step 5.

**Click Here to View Inground Pool Pumps**

For a RECTANGULAR POOL:

Measure the length (ft), the width (ft) and the average depth. The average depth is determined by adding the depth at the shallow end to the depth at the deep end and dividing by two.

The formula for calculating the total gallons in a rectangular pool is: Gallons = Length x Width x Average Depth x 7.5.

For example (see picture): your pool is 30 ft long and 15 ft wide. The pool's shallow end is 4 ft and its deep end is 8 ft. So, the pool's average depth is 4 plus 8 = 12 divided by 2. This gives you 6 ft. The pool's capacity is 30 ft x 15 ft x 6 ft x 7.5 = 20,250 gallons. Go to Step 5.

For a ROUND SWIMMING POOL:

Determine the number of gallons of water in your round pool, measure the diameter of the pool and its average depth. The average depth is determined by adding the depth at the shallowest part to the depth at the deepest part and dividing by two.

The formula for calculating the total gallons in a round pool is: Gallons = Diameter x Diameter x Average Depth x 5.9.

For example (see picture): your pool is 25 ft in diameter, the pool's shallow end is 3 ft and its deep end is 7 ft. So the pool's average depth is 3 plus 7 = 10 divided by 2. This gives you 5 ft. The pool's capacity is 25 ft x 25 ft x 5 ft x 5.9 = 18,428 gallons. Go to Step 5.

**Click Here to View Inground Pool Pumps**

Determine the number of gallons of water in your round pool, measure the diameter of the pool and its average depth. The average depth is determined by adding the depth at the shallowest part to the depth at the deepest part and dividing by two.

The formula for calculating the total gallons in a round pool is: Gallons = Diameter x Diameter x Average Depth x 5.9.

For example (see picture): your pool is 25 ft in diameter, the pool's shallow end is 3 ft and its deep end is 7 ft. So the pool's average depth is 3 plus 7 = 10 divided by 2. This gives you 5 ft. The pool's capacity is 25 ft x 25 ft x 5 ft x 5.9 = 18,428 gallons. Go to Step 5.

For an OVAL SWIMMING POOL:

To determine the number of gallons of water in your oval pool, measure the longest diameter, the shortest diameter and the average depth. The average depth is determined by adding the depth at the shallow end to the depth at the deep end and dividing by two.

The formula for calculating the total gallons in an oval pool is: Gallons = Longest diameter x Shortest diameter x Average depth x 6.7.

For example (see picture): Your pool's longest diameter is 25 ft, shortest diameter is 15 ft and the pool's average depth is (3 + 7) / 2 = 5 ft. The pool's capacity is 25 x 15 x 5 x 6.7 = 12,563 gallons. Go to Step 5.

**Click Here to View Inground Pool Pumps**

To determine the number of gallons of water in your oval pool, measure the longest diameter, the shortest diameter and the average depth. The average depth is determined by adding the depth at the shallow end to the depth at the deep end and dividing by two.

The formula for calculating the total gallons in an oval pool is: Gallons = Longest diameter x Shortest diameter x Average depth x 6.7.

For example (see picture): Your pool's longest diameter is 25 ft, shortest diameter is 15 ft and the pool's average depth is (3 + 7) / 2 = 5 ft. The pool's capacity is 25 x 15 x 5 x 6.7 = 12,563 gallons. Go to Step 5.

For a KIDNEY-SHAPED SWIMMING POOL:

To determine the number of gallons of water in your kidney-shaped pool, measure the largest width, the smallest width and the average depth. The average depth is determined by adding the depth at the shallow end to the depth at the deep end and dividing by two.

The formula for calculating the total gallons in a kidney-shaped pool is: Gallons = (Longest width + Shortest width) x Length x Average depth x 3.38.

For example (see picture): Your pool's length is 25 ft, longest width is 15 ft, shortest width is 10 ft and the pool's average depth is (3 + 7) / 2 = 5 ft. The pool's capacity is (15 + 10) x 25 x 5 x 3.38 = 10,563 gallons.

**Click Here to View Inground Pool Pumps**

To determine the number of gallons of water in your kidney-shaped pool, measure the largest width, the smallest width and the average depth. The average depth is determined by adding the depth at the shallow end to the depth at the deep end and dividing by two.

The formula for calculating the total gallons in a kidney-shaped pool is: Gallons = (Longest width + Shortest width) x Length x Average depth x 3.38.

For example (see picture): Your pool's length is 25 ft, longest width is 15 ft, shortest width is 10 ft and the pool's average depth is (3 + 7) / 2 = 5 ft. The pool's capacity is (15 + 10) x 25 x 5 x 3.38 = 10,563 gallons.

Now that you have calculated the number of gallons in your swimming pool, you want to determine how many gallons per hour (GPH) you need to pump to clean all the water in your pool in eight hours. To come up with this flow rate, simply divide your calculated gallons by eight. For the RECTANGULAR swimming pool example the GPH required is 20,250 gallons / 8 hours or 2531 GPH.

**Click Here to View Inground Pool Pumps**

Most pool pump specifications are expressed in gallons per minute (GPM). So, to convert from GPH to GPM, divide your GPH by 60 minutes - 2531 GPH / 60 = 42.2 GPM.

**Click Here to View Inground Pool Pumps**

Having calculated your required GPM, you next have to figure out the average Feet of Head for your pool pump. Check out our blog on How to Calculate Feet of Head. PLEASE NOTE, WE ARE CURRENTLY REVIEWING OUR PROCEDURE FOR ESTIMATING FEET OF HEAD. CURRENT ESTIMATES ARE TOO HIGH.

**Click Here to View Inground Pool Pumps**

You now have the information required to select the size of your pool pump. Go to the description page of the style of pump you would like to purchase. Many pump manufacturers will provide a chart on this description page showing the HP required for your particular GPM and Foot of Head. For example, say you wanted the popular Hayward Super Pump (an abbreviated version of the Hayward Super Pump performance page is shown at the left). Based on the data calculated above for a typical RECTANGULAR pool, we are looking for a pump that will handle 42GPM with a 47 Feet of Head. According to the chart for 50 Feet of Head (closest to 47'), we need a pump between 3/4 HP (31 GPM) and 1 HP (50 GPM). Since we always go for the higher GPM, we would select the 1 HP pump.

**Click Here to View Inground Pool Pumps**

The full performance page for the Hayward Super Pump can be found at this link, Hayward Super Pump. For the location of performance pages for other pump models, contact an Inyopools sales representative at 1-877-372-6038.

**Click Here to View Inground Pool Pumps**

The size of your pool filter is directly related to the pool pump you have selected. If your pool filter is too small for the pump, there will be additional strain on the pump motor as it tries to push water through and encounters resistance at the filter. This will eventually burn out the pump motor and your filtration will also be compromised. We recommend selecting the filter so that it is oversized to be absolutely certain it can handle the flow coming from the pump. So, in this case, instead of getting a filter rated at exactly 42 GPM, you should select one that is a little higher – around 60 GPM would be fine.

**Click Here to View Inground Pool Pumps**

There are a couple of other considerations that should be mentioned in your selection of a pool pump. The above calculations are based on a basic pool configuration with no extra water features like: fountains, spas, waterfalls, solar heating, and in-floor cleaning systems. These features generally require higher GPM rates which equate to a higher HP pump. Also if your pool requires greater than 60 GPM you may need at least 2" diameter suction pipes. Suction pipes of 1 1/2" have a physical limit of 60 GPM. 2" pipes can handle up to 100 GPM.

**Click Here to View Inground Pool Pumps**

InyopoolsPosted: 5/8/2018Reply

HydroxPosted: 5/4/2018Reply

INYOPoolsPosted: 4/25/2018Reply

RyanPosted: 4/24/2018Reply

InyopoolsPosted: 4/23/2018Reply

InyopoolsPosted: 4/23/2018Reply

mikePosted: 4/23/2018Reply

PetePosted: 4/21/2018Reply

Derek DewittPosted: 3/28/2018Reply

InyopoolsPosted: 3/26/2018Reply

william millerPosted: 3/24/2018Reply

InyopoolsPosted: 3/21/2018Reply

LARRYPosted: 3/12/2018Reply

InyopoolsPosted: 3/7/2018Reply

CliffPosted: 3/6/2018Reply

CliffPosted: 3/4/2018Reply

InyopoolsPosted: 2/10/2018Reply

RandyPosted: 2/9/2018Reply

InyopoolsPosted: 1/29/2018Reply

InyopoolsPosted: 1/29/2018Reply

SuzyPosted: 1/28/2018Reply

EfficiencyPosted: 1/26/2018Reply

InyopoolsPosted: 12/11/2017Reply

InyopoolsPosted: 12/11/2017Reply

DanPosted: 12/8/2017Reply

MarcPosted: 12/6/2017Reply

InyopoolsPosted: 11/13/2017Reply

AnonymousPosted: 11/7/2017Reply

InyopoolsPosted: 10/22/2017Reply

ANAPosted: 10/19/2017Reply

InyoPools Product Specialist

Mr, Vinegar - We would recommend the larger PureLine Prime 2.7 HP Variable Speed Pool Pump.Dennis R.Posted: 10/4/2017Reply

Mr. VinegarPosted: 9/29/2017Reply

InyoPools Product Specialist

Lu - Your pool would hold about 7200 gallons of water. For that size pool, we would recommend a cartridge pump/filter set like the "Hayward Super Pump 1 HP SINGLE Speed W/ C1200 120 Sq. Ft. Cartridge Filter' or a sand pump/filter set like the "Hayward Super Pump 1 HP Single Speed W/ S244T 24" Sand Filter & Valve".Dennis R.Posted: 9/15/2017Reply

LuPosted: 9/10/2017Thanking you,

Regards

Lu

Reply

InyoPools Product Specialist

Jynxy - The more I read on calculating head, the more I'm convinced that they are too many variables in the calculation to come up with anything more than a good guess on your system's head. Many experts say to use 40' to 50' as a good approximation and leave it at that. We are still looking into it, but don't have any better rationale than that at this time. That being said, for your size pool, I would recommend installing 2" pipes and buying the smaller Hayward Tristar VSP 1.85 HP pump. I would also recommend buying a larger filter in the range of 100 GPM to lessen the chance of blowing out the filter. Most pool designers recommend getting a filter that is 25% larger than your pump's capacity. This pump can operate at 80-100 GPM at full speed. You would probably be running it at lower speeds most of the time, so this would give you a good filter cushion. And, a sand filter is probably the easiest to clean/maintain until you have to change the sand every 5-7 years. The cartridge filter filters better than sand but you have to lift out and clean the cartridge every month or so which is a little more time-consuming.Dennis R.Posted: 8/20/2017Reply

JynxyPosted: 8/14/2017Reply

InyoPools Product Specialist

Novalove1 - If you were happy with your old pump, I would replace it with the same Pentair SuperFlo 1 HP Single Speed Pump. If you are interested in saving 20% in operational costs, I would recommend the Energy Efficient (EE) model, Pentair SuperFlo 1 HP EE Single Speed Pump.Dennis R.Posted: 8/7/2017Reply

Novalove1Posted: 8/4/2017Reply

InyoPools Product Specialist

Gilbert - Can you give me more information on this pump?Dennis R.Posted: 7/21/2017Reply

GilbertPosted: 7/19/2017Reply