Table Salt vs Pool Salt: What You Can Use
Not ordinary table salt: it is usually iodized or has an anti-caking agent added, and salt chlorinator makers tell you to avoid both. Use plain sodium chloride (NaCl) that is at least 99.8% pure with no additives (Pentair's wording) or more than 99% pure (Hayward's), and follow the manual for your own cell.
Always follow your product’s label directions. Pool and spa chlorine, bromine, shock and algaecides are EPA-registered pesticides: use products labeled for pool or spa use, and don’t swim or soak until levels are within the limit on your product’s label. If this page and a label disagree, the label wins.
On this page (8 sections)
A saltwater pool turns dissolved salt into chlorine inside a salt cell (also called a salt chlorine generator). The cell only needs sodium chloride. Everything else in the bag, from iodine to anti-caking powder, can stain surfaces or wear the cell. Here is what the two big chlorinator brands say, and how common salts compare.
What the cell makers say
The two manuals below are for current salt chlorinators. They agree on the main points but differ on the purity number, so read the manual that came with your cell.
- Pentair IntelliChlor: "Use at least 99.8% pure sodium chloride." Pentair recommends an evaporated, granulated, food-quality, non-iodized salt with no additives. It says to avoid salt with anti-caking agents, because filling agents can discolor fittings and pool finishes. It also says not to use rock salt, because impurities can shorten the cell's life, and not to use calcium chloride, sodium bromide or potassium chloride.
- Hayward Aqua Rite: use only sodium chloride that is greater than 99% pure. Do not use rock salt, salt with yellow prussiate of soda, salt with anti-caking additives, or iodized salt.
Both allow water conditioning salt pellets (the kind used in water softeners) but say they dissolve more slowly. Pentair adds that pellets could damage pool plaster and other surfaces. Neither manual says table salt is allowed, and iodized salt is ruled out in plain words.
Salt types compared
The table lines up the salts people ask about with what we could confirm from the makers' documents. A "—" means we found no number from a maker or a label.
| Salt | Purity (NaCl) | Anti-caking or iodine | Risk to cell or pool, per the makers |
|---|---|---|---|
| Pool salt, evaporated, no additives | Pentair asks for at least 99.8% | None | The kind both makers describe |
| Plain water softener pellets | Check the bag | Check the bag | Allowed by both makers; slow to dissolve; Pentair warns about plaster |
| Softener pellets with cleaning additives (for example Morton Clean and Protect) | 99.65% minimum | Resin cleaning additives | We could not confirm that either maker accepts the additives |
| Rock salt | — | — | Both makers say do not use |
| Iodized table salt (Morton) | — | Calcium silicate, dextrose, potassium iodide | Hayward bans iodized and anti-caking salt; Pentair says avoid anti-caking agents |
| Sea salt | — | — | No maker rating found; compare the bag with the cell's purity number |
| Epsom salt | Not NaCl | — | Magnesium sulfate, not sodium chloride, so a salt cell can't use it |
Table salt ingredients are from Morton's own page for its iodized table salt. Pellet purity is from Morton's product data sheet for Clean and Protect. We did not buy or lab-test any salt.
Why additives matter
Anti-caking agents keep salt from clumping in a shaker. In a pool they are just extra solids. Pentair names the visible result: they can discolor fittings and pool finishes. Iodine and the sugar (dextrose) that stabilizes it in iodized salt are also not what a cell is made for, and Hayward rules iodized salt out. Rock salt is mined and contains more non-salt material, which Pentair says can shorten the cell's life.
The same table salt is fine on the dinner table. For a pool, the question is only what the bag lists besides sodium chloride.
If you only have table salt
Don't put iodized or anti-caking table salt into a chlorinator pool. If you are not sure what is in a salt, read the ingredient list: it should say "salt" or "sodium chloride" and nothing else. Some salts sold for food use list only sodium chloride. We did not check any brand's purity, so confirm that the bag meets your cell maker's number before using it.
If a bag of table salt has already gone in, don't panic. Run the pump, test the water, and ask the cell's maker whether that amount matters for your model. We can't say how much is harmless.
How much salt, and what it costs per 1,000 gallons
Hayward's chart gives 213 lb of salt for 8,000 gallons going from 0 to 3,200 ppm, which is 26.7 lb per 1,000 gallons. Hayward says the ideal range is 2,700–3,400 ppm, with 3,200 ppm optimal. Pentair warns that levels above 6,000 ppm can speed up corrosion of equipment and discolor pool surfaces.
To compare prices, work out the cost per 1,000 gallons from the bag price. It is the price divided by the bag weight, times 26.7:
| Bag size | Bags needed per 1,000 gal | Cost per 1,000 gal |
|---|---|---|
| 40 lb | 0.67 | bag price × 0.67 |
| 50 lb | 0.53 | bag price × 0.53 |
| 80 lb | 0.33 | bag price × 0.33 |
We did not collect current bag prices, because they change by store and week. Multiply your own price. Test your starting salt first, since tap water and past chemicals add some. The pool salt calculator works out bags for your volume and starting level.
Other things worth knowing
- Pour salt around the edge of the pool, not through the skimmer. Brush it and run the pump for 24 hours before reading the cell's display. This is Pentair's procedure.
- Test salinity with a meter calibrated for sodium chloride. Strips and meters can disagree, so keep using the same method.
- Wait before adding salt to a newly surfaced plaster pool: Pentair says at least one month, and Hayward says 10 to 14 days. Follow your pool surface maker's guidance.
- Salt does not evaporate. You only lose it when water leaves, from splashing, backwashing and draining.
Learn the routine in salt water pool maintenance, the right target by brand in pool salt level, and how cells are cleaned in cleaning a salt cell. Weighing the switch? See salt water vs chlorine pool.
FAQ
Can I use table salt in my saltwater pool?
Not iodized table salt, and not salt with anti-caking additives. Hayward and Pentair both tell you to avoid anti-caking additives, and Hayward lists iodized salt as off limits.
Can you use rock salt in a pool?
No. Both Pentair and Hayward say not to use rock salt. Pentair adds that its impurities can reduce the life of the cell.
Can you use water softener salt in a pool?
Both makers allow water conditioning salt pellets, but they dissolve more slowly. Pentair warns they could damage plaster. Check the bag, because some pellets contain cleaning additives.
Is pool salt the same as sea salt?
No, they are not the same product. Pentair asks for at least 99.8% sodium chloride with no additives. We found no purity rating from a chlorinator maker for sea salt, so check the bag against your manual.
Can I put Epsom salt in a pool?
Epsom salt is magnesium sulfate, not sodium chloride, so it does not feed a salt cell. We found no maker that recommends it for pools.
Sources
- Pentair, IntelliChlor Plus and LT installation and user's guide (salt type, 6,000 ppm warning, adding salt): pentair.com (PDF)
- Hayward, Aqua Rite electronic chlorine generator manual (salt type, 2,700–3,400 ppm, salt table): hayward.com (PDF)
- Morton Salt, iodized table salt ingredients: mortonsalt.com
- Morton Salt, Clean and Protect water softening pellets, product data sheet (99.65% minimum, cleaning additives): PDF