Adding Salt to your Swimming Pool

Posted by Robert J. on 3/1/2011 to Salt Pool Need-to-Know

So, you are converting your pool to salt and have purchased a saltwater chlorine generator. You know you have to add salt, but what kind should you get? How much salt should you add? This guide will tell you all you need to know, as well as some tips and tricks to help along the way.

Kinds of salt suitable for use in swimming pools, such as morton pool salt, aqua salt brand, water softener crystals, diamond crystal brand pellets
Morton and Diamond Crystal are popular, readily available, and inexpensive brand of salt for use in pools

Determine your Optimum Salinity Level

Depending on the manufacturer, salt pool systems can work in salt levels from 3000 to 5000 parts per million (ppm). Since there are a few different popular salt systems, it is important to check your Salt Chlorinator owner’s manual to see what the recommended salinity is. Since the majority of chlorinators operate efficiently at a salinity of between 3000 ppm and 4000 ppm, our target will be 3500 ppm (which is what the great majority of systems say the pool should be kept at, despite the varying ranges published).

Check for any Existing Salt Levels

Next, we need to ascertain how much salt is in the pool. While it's a safe bet that a pool that has new water will generally have close to no salt level present, its possible pools in some areas can naturally acquire up to 500 ppm over time. To be safe, it's best to check. You will want to get some Salt Water Test Strips so that you can test the salinity of the water. Most pool stores offer free water testing services, so alternatively you could just take a sample in for a more accurate result.

Determine Pool Size & Amount of Salt

The next thing we need to know is how many gallons of water are in the pool. If you're not sure, you can use the following formulas to estimate:

Rectangular Pool - Length x Width x Average Depth x 7.5
Round Pool - Diameter x Diameter x Average Depth x 5.9
Oval Pool - Length x Width x Average Depth x 6.7

Assuming you have fresh water in the pool and the goal is 3500 ppm, you need to add 30lbs of salt for every 1000 gallons of water. So, if you have a 20,000 gallon pool and want to calculate how much salt you will need to purchase, you would multiply 20*30=600. Therefore, the pool would require approximately 600 lbs of salt.

What Kind of Salt to Use

Time to buy some salt! You can of course use "Pool Salt", but itWater Softener Salt is less expensive, virtually identical, and widely available (Home Depot, Sam’s Club, Costco, Lowe’s, Wal-Mart. It generally comes in 40lb. bags. This would mean we need to buy 15 bags of salt for our 20,000 gallon pool. Always use non-iodized salt that is at least 99.8% pure sodium chloride (NaCl). Avoid any salt with anti-caking agents or extra "special formula" additives as they can cause staining in your pool.

Adding the Salt

If you have already installed your Salt Water Chlorine Generator, make sure that you keep it in the OFF position until the salt has dissolved. You should only pour the salt into the direct body of the pool, concentrating on the shallow end of the pool where it will be easier to dissolve. The finer the salt granules, the faster it will dissolve. We recommend running the pump for at least 24 hours to make sure that the salt has completely dissolved. It is important to keep the pump running to help circulate and dissolve the salt. Never pour salt into the skimmer.

TIP: It's not necessarily the best to dump 100% of the salt in that you bought. There may have been some margin of error in your calculations. Add maybe 90%, let the salt dissolve, and then retest your salt level before adding your last bag or two. If the salt level gets too high, your only recourse is to drain some water and dilute with fresh water!

bags of salt to convert swimming pool to a saltwater chlorine generator
It is always easier to add more salt later if necessary

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