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 what you need to know, as well as some tips and tricks to help along the way.
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 vast majority of systems say the pool should be kept at).
Check for any Existing Salt Levels
Next, we need to ascertain how much salt might currently be in the pool. While it's a safe bet that a pool with new water will generally have close to a zero 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 Saltwater Test Strips so that you can test the current salinity of the pool 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 & Quantity of Salt Needed
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
TIP: Have a lagoon or kidney shape pool? Try estimating the pool size like an oval shape if you can't find your pool's records.
Assuming you have zero existing salinity 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 determine how much salt you will need to purchase, you would calculate 30 / 1,000 x 20,000 which equals 600. Therefore, the pool would require approximately 600 lbs of salt.
What Kind of Salt to Use
Time to buy some salt! You can use anything labeled "Pool Salt", but also consider "Water Softener Salt". It is less expensive, virtually identical, and widely available (Home Depot, Sam’s Club, Costco, Lowe’s, Wal-Mart. Regardless, $5-$7 a bag is very common to expect. Salt generally comes in 40lb. bags, so for our example this would mean we need to buy 15 bags of salt for our 20,000 gallon pool. Just a few more details: always use non-iodized salt that is at least 99.8% pure sodium chloride (NaCl), and 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 the controls set to "OFF" 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 idea to dump in 100% of the salt that you bought. There may have been some margin of error in your pool size measurements. 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 the pool with new water!