Converting a pool to saltwater changes where the chlorine comes from, not whether the pool has it. A salt chlorine generator makes chlorine inside a cell on the equipment pad, so nobody buys and pours it by hand, but the water still has to carry free chlorine and still has to be tested. For a Central Texas pool, the conversion itself is a small equipment job, and the part worth planning for is the hard water.
We install salt systems as part of our energy efficient equipment work, and most questions about them come from one misunderstanding: that a salt pool is a chemical-free pool. It is not.
How a salt system makes chlorine
A salt system runs dissolved salt through an electrolytic cell and turns it into chlorine. Pentair describes the power center on its IntelliChlor units as converting household AC current to the low-voltage DC current the cell needs to produce chlorine. The salt stays in the water and goes through the cell again.
That loop only runs while water moves. Pentair states plainly that the pool pump must be running for the generator to provide chlorine, and that the unit does not monitor or control chlorine levels on its own. The cell produces chlorine at the output you set, and whether that is the right amount is still a question for a test kit.
How salty is a saltwater pool?
A saltwater pool runs at roughly a tenth of the saltiness of the ocean. Hayward gives the ideal range for its AquaRite systems as 2,700 to 3,400 ppm, with 3,200 ppm optimal, and Pentair recommends 3,600 ppm for its IntelliChlor cells. The U.S. Geological Survey puts seawater at about 35,000 ppm.
The target matters in both directions. Pentair says its cell turns off and makes no chlorine below 2,600 ppm, and that above 4,500 ppm salt may cause excessive corrosion or deterioration to equipment and surfaces in and around the pool. Hayward notes that salt generally starts to be tasted at about 3,500 to 4,000 ppm. Use the number your cell manufacturer publishes.
A saltwater pool is still a chlorine pool. The difference is that the chlorine is made at the pad instead of carried home in a jug.
What you still test every week
The test routine on a salt pool looks almost exactly like the routine on any other chlorinated pool. Hayward’s maintenance table for the AquaRite calls for these checks:
- Weekly: free chlorine at 1.0 to 3.0 ppm and pH at 7.2 to 7.8.
- Monthly: total alkalinity at 80 to 120 ppm, and the salt level itself.
- Quarterly: stabilizer at 30 to 50 ppm, calcium hardness at 200 to 400 ppm, and an inspection and cleaning of the cell.
Pentair’s guide points to the APSP recommendation of 2.0 to 4.0 ppm free chlorine instead, so check the range printed for the system you actually own. Test salt with a separate kit as well as the display, because Pentair rates its salt sensor at plus or minus 500 ppm.
Stabilizer earns its place on that list in Texas sun. Pentair says 90 percent of unstabilized chlorine is destroyed by ultraviolet light within two hours, which is why it asks for cyanuric acid at 30 to 50 ppm on outdoor pools.
Why hard water is the part that matters here
Scale on the cell is the maintenance item that decides how a salt system lives in Central Texas. Austin Water reports total hardness between 70 and 126 ppm, averaging 93 ppm or about 5.4 grains per gallon, and a pool concentrates that as water evaporates and is topped up through the summer.
Pentair describes scale as a white crusty deposit that forms on the cell blades in excessively hard or out of balance water. Pentair recommends pulling the cell to inspect it every two months, more often in hard water areas, and at least twice a year even once it stays clean. A cell that is easy to reach on the pad gets inspected.
When to convert, and when to wait
The best time to convert is either on a pool that is running normally or after a new plaster finish has fully cured. Salt and fresh plaster do not mix. Hayward says to wait 10 to 14 days after new plaster before adding salt, and Pentair says to wait at least one month, warning that salt is corrosive and severe damage can occur. When those two differ, follow the longer one and the plaster manufacturer’s own guidance.
That makes a pool renovation a natural moment to plan the change and a bad moment to rush it. If you are replastering anyway, as covered in our post on when to replaster a pool, the cell and power center can be plumbed in during the renovation and left off until the finish has cured.
Pentair’s cell will not produce chlorine below 52 degrees Fahrenheit, so a conversion started in a January cold snap sits idle until the water warms. Autumn or spring avoids that.
Sizing the cell and the pump
A salt cell is sized to the pool volume, and it helps to size up. Pentair rates its IC20 cell for pools up to 20,000 gallons at 0.70 pounds of chlorine per 24 hours, and its IC40 for pools up to 40,000 gallons at 1.40 pounds. A larger cell running at a lower output setting rests more of the time, and Pentair designs its cells for approximately 10,000 hours of operation, roughly five years of average use.
Flow is the other half. Pentair designs the IntelliChlor for flow from 25 up to 105 gallons per minute and requires a bypass loop above 80, which comes up on pools with in-floor cleaning or booster pumps. Add salt only as sodium chloride greater than 99 percent pure, as Hayward specifies, brush it in, and let it circulate for 24 hours before trusting the reading.
If you are considering a conversion, send us the pool size, a photograph of the equipment pad and a recent water test. That tells us which cell fits, whether the plumbing needs anything, and whether the timing lines up with other work the pool is due for.
