How to Size a Salt Chlorine Generator for My Pool

May 9, 2016

3 Minute Read

Hello prospective salt chlorine generator owner, I hope all is well and your search for the best brand for your pool is on track. This article will teach you how to size a salt chlorine generator properly for an in-ground pool. The process involves figuring out your pool’s volume in gallons. This process requires a little bit of math, but do not fear, we will walk you through the formulas so no one gets lost along the way. Once we have the pool’s volume set, we can decide what is the best size salt chlorine generator for our particular pool. For more information regarding converting a pool to saltwater, read our article called: The Ultimate Guide to Converting Your Pool to Saltwater

Pool Volume

Salt chlorine generators are rated for the maximum amount of gallons a salt cell can chlorinate. For example, the Pentair IntelliChlor models IC20, IC40, and IC60 are capable of chlorinating 20,000; 40,000; and 60,000 gallons respectively.

Now not all pools are rectangular, you may have an oval, round or kidney-shaped pool. For each one of these shapes there is a volume formula, and below I have listed each:

Rectangle – Length x Width x Average Depth x 7.5
Round – Diameter x Diameter x Average Depth x 5.9
Oval – Longest Diameter x Shortest Diameter x Average Depth x 6.7
Kidney – Length x Average Width x Average Depth x 7.0

For example, let us say I have an oval pool with the longest length being 36 feet and the widest width being 18 feet with an average depth of 5.5 feet. What is the volume of my pool?

Using the formula for ovals, let’s break it down:

Oval – Longest Diameter x Shortest Diameter x Average Depth x 6.7
36 Feet x 18 Feet x 5.5 x 6.7 = 23 878.8 gallons

For the sake of having a nice round number moving forward, we will round the sum product up to 24,000 gallons of water.

Which Salt Chlorine Generator to Choose?

Our pool from the example is 24 000 gallons. If we were sizing our pool for an AquaRite system, we would have two choices – the AquaRite 25K and the 40K. Which is the correct choice?

The correct answer is the Crystal Pure 40K.

But Why?

Look at it this way, do you travel a further distance walking at a moderate pace or sprinting? You tire quicker the harder you push yourself and the same principle applies to your salt cell. Be kind, oversize.

If you’re a regular reader of this blog (and I hope that you are) you know that we suggest oversizing some parts of your equipment, specifically your filter, heater and your salt chlorine generator. The basic logic for each is that by oversizing the filter, you can go much longer between cleaning and by upsizing a heater you can heat your pool quicker, thereby saving money by removing the need to run your pool pump to feed your heater. And by oversizing a salt cell you allow the cell to work at a fraction of its full capacity rather than at full pace to keep up the chlorine levels. This throttling of the cell allows the cell to last longer, hopefully pushing the cell’s lifespan over the expected cell life expectancy of three to five years.

Well, that about covers it for sizing salt chlorine generators. If you have any questions about SCGs or anything else pool-related, feel free to leave a comment or give us a call at 877-372-6038.

Matthew Simmons Technical Writer & Pool Product Expert

Swimming pool expert at InyoPools and host of Poolside Chat, brings over a decade of experience in the pool industry.

See Full Bio