# How to Size a swimming pool Pump on your In-Ground Pool Step 1

The first thing is to determine the number of gallons of water in you pool. The formulas for calculating gallons be based upon the shape of your respective pool. For any RECTANGULAR POOL, measure the space (ft), the width (ft) and the average depth. Average depth is determined by adding the depth at the shallow end towards the depth at the deep end and dividing by 2. The formula for calculating total gallons in a rectangular pool is: Gallons = Length x Width x Average Depth x 7.5 Example (see picture): your pool is 30 ft long and 15 feet wide; the pools shallow end is 4 ft and it is deep end is 8 ft and so the pools average depth is 4 plus 8 = 12 divided by 2 = 6 ft. Pools capacity is 30 ft x 15 ft x 6 ft x 7.5 = 20,250 gallons. Head to Step 5

Step 2

ROUND Pool To discover the number of gallons of water in your round pool, measure the diameter on the pool and its particular average depth. Average depth depends upon adding the depth in the shallowest part towards the depth at the deepest part and dividing by 2. The formula for calculating total gallons within an oval pool is: Gallons = Diameter x Diameter x Average Depth x 5.9. Example (see picture): your pool is 25 ft in diameter; the pools shallow end is 3 ft and it is deep end is 7 ft hence the pools average depth is 3 plus 7 = 10 divided by 2 = 5 ft. Pools capacity is 25 ft x 25 ft x 5 ft x 5.9 = 18,428 gallons. Go to Step 5

Step 3

OVAL Swimming bath To look for the amount of gallons of water inside your oval pool, measure the long diameter, the short diameter as well as the average depth. Average depth relies on adding the depth at the shallow end for the depth at the deep end and dividing by 2. The formula for calculating total gallons within an oval pool is: Gallons = Long diameter x Short diameter x Length x Average depth x 5.9. Example (see picture): Your pools long diameter is 25 ft, Short diameter is 15 ft as well as the pools average depth is (3 + 7) / 2 = 5 ft. Pools capacity is 25 x 15 x 5 x 5.9 = 11,063 gallons. Check out Step 5

Step 4

KIDNEY SWIMMING POOL To discover the variety of gallons of water within your kidney pool, measure the most important width, the littlest width plus the average depth. Average depth is determined by adding the depth in the shallow end towards depth in the deep end and dividing by 2. The formula for calculating total gallons in the kidney pool is: Gallons = (Longest width + Shortest width) x Length x Average depth x 3.38. Example (see picture): Your pools length is 25 ft, longest width is 15 ft, Shortest width is 10 ft and also the pools average depth is (3 + 7) / 2 = 5 ft. Pools capacity is (15 + 10) x 25 x 5 x 3.38 = 10,563 gallons

Step 5

Now that youve got calculated the number of gallons within your swimming bath, you want to determine how many gallons per hour (GPH) you have to pump to wash each of the water within your pool in 8 hours. To think of this flow rate simply divide your calculated gallons by 8. For the RECTANGULAR childrens pool example the GPH required is 20,250 gallons / 8 hours or 2531 GPH.

Step 6

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

Step 7

Having calculated your required GPM, you next ought to discover the common Feet of Head on your pool pump. A fantastic estimate is always to consider the average volume of feet from where your suction line is (skimmers or main drain) to where your pool pump are going to be located. The image on the right provides an demonstration of that this average Feet of Head would be calculated to get a pool with 3 suction returns, two skimmers and something main drain. The lengths of every line are: Skimmer 1 5+15+25+15+10 = 70; Skimmer 2 15+10 = 25; and Main Drain 25+20 = 45. To obtain the average Feet of Head grab the three suction line lenghts and divide by three. 70 + 25 + 45 = 140 / 3 = 47 Average Feet of Head

Step 8

You have the details forced to find the measurements your pool pump. See a description page from the kind of pump you wish to purchase. One example is, say you desired the widely used Hayward Super Pump. An abbreviated version in the Hayward Super Pump Performance Page is shown on the left. Using the chart for 50 Feet of Head (closest to 47), we start to use a pump between 3/4 HP (31 GPM) and 1 HP (50 GPM). Since we always proceed to the higher GPM, we will find the 1 HP pump.

Step 9

The complete Performance Page for your Hayward Super Pump are available at this link, Harward Super Pump . For the location of Performance Pages for other pump models, contact an Inyopools salesperson at 1-877-372-6038.

Step 10

The length of your pool filter is directly related on the pool pump youve got selected. If the pool filter is simply too small for your pump, you will see additional strain for the push mainly because it tries to push water through and meets resistance with the filter. It will eventually blow out the water pump as well as your filtration also are compromised. We recommend over-sizing the filter for being very sure it could handle the flow from the pump.

Step 11

There is a several other considerations that ought to be mentioned in your variety of a swimming pool pump. The characteristics generally require higher GFM rates which equates to a greater HP pumps. Also in case your pool requires more than 60 GFM youll need a minimum of 2″ diameter suction pipes. Suction pipes of 1 1/2″ use a physical limit of 60 GPM. 2″ pipes are designed for approximately 100 GPM.