Stay away from Clorox pool salt.
Mortons pool salt and Diamond Crystal pool salt are good.
If this is not fresh new water then check your salt level with the
K-1766 Taylor Salt Test before you add any salt. You may have more salt in your water then you expect.
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Salt can be added using solar salt, sold for use in water softeners (sodium chloride). You want the kind that is 99.4% pure or better and which doesn't have any rust inhibitor or other additives. Crystals are fine. Pellets will work but dissolve slightly more slowly.
The purer the salt, the better the life and performance of the Chlorine Generator. Use salt that is at least 99.8% pure NaCl, sodium chloride. The preferred and recommended salt is an evaporated, granulated, food quality, non-iodized salt with no additives.
- Avoid using salt with anti-caking agents (sodium ferrocyanide, also known as YPS or yellow prussiate of soda). Filling agents can cause some discoloration of fittings and surface finishes in pool.
- Water conditioning salt pellets are compressed forms of evaporated salt and may be used, but will take longer to dissolve. Such pellets could damage pool plaster and other surfaces in and around the pool.
- Do not use calcium chloride or potassium chloride as a source of salt. (Use sodium chloride only).
- Do not use Rock salt (insoluble impurities mixed with the rock salt can shorten the life of the Cell)
Pool store salt generally costs more and is more finely ground, but even pellets dissolve quickly enough so that isn't really any advantage. Be aware that salt is a naturally mined or harvested (from slat flats) product.
The type of salt sold for pools is not a highly pure chemical grade of salt and therefore will have some impurities in it form the mining process.
If you are doing an SWG pool startup process, then you could be adding hundreds of pounds of salt to your pool. Even if your salt is 99.5% pure, then every 100 lbs of salt added will add 1/2 pound of “impurities”. This can often lead to cloudy water that will take time for your filter to remove. Most of these impurities are just silica dust or other non-toxic compounds.
Clorox Pool Salt has been reported by multiple members to stain pools.