How to size a salt chlorine generator

How to Size a Salt Chlorine Generator for My Pool

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?which salt chlorine generator should I 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.

11 thoughts on “How to Size a Salt Chlorine Generator for My Pool

  1. Hi, how would you size salt chlorine generator commercial pool that’s 142000 gallons?
    Is there a formula. It seems like most of the products sold are too small.
    Would I need to buy 5 x 40,000-gallon units and install them in serie or parallel?
    What is the required salt level for a commercial pool 3500ppm or 5000ppm?

      1. Hi Matthew,
        Thanks for the quick reply. I definitely check out autopilot.

        In my country, there aren’t any local codes regarding swimming pools. So I wanted to know what are the general baseline codes for commercial pools in the U.S.

        But besides for commercial. How would you size a salt system for residential pools is it’s just based max pool volume it can handle or is it based on the system’s max chlorine production.

        Also is there a formula for calculating the amount of chlorine needs to be produced per day for a salt pool.

  2. Hello I have a 168,000 gal pool with 3 pump and 3 sand filter and I am trying to find out how much chlorine I need to generate and what type of Salt cells I need. Can you assist me plz.

  3. I have a question. I have a 12,000 in-ground pool. The T-5 that is sized for 20,000 says that it is for above ground pools. Is there a reason why I can’t use this T-cell for my inground pool? I’m not clear on what the difference could be…

  4. My community pool has been remodeled in the last year with all new filtering equipment. We did not go with a salt system, just came back with a chlorine system. When I asked why not salt, I was told because our pool size has 220,000 gallons and that size is much too large for a salt system. I want to know if that information is correct, and would like to know the maximum pool size in gallons for a salt system. I think someone forgot to consider changing to salt and is possibly telling me that salt story to cover up what might be a blunder on some project manager’s part.

    1. If you scroll up a couple of comments you will see my answer to a question very similar to this, with more info. Yes, there are systems available for pools that size. Amount of cells needed is also dependent on bather load.

      1. We are currently looking into salt systems for the pool at our condo. Chlorine and chemical costs have gone up considerably in the past year. It is a very large pool and we are located in an area that has lots of sunshine and high temperatures. One of the considerations we have to take into account is the overall cost for the conversation from Chlorine to salt. In that regard can you accurately tell me the life expectancy of the salt cells and what would the life expectancy of the system be.
        Thanks

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