Salt Water Pool Systems

How a salt system works

A salt chlorine generator has two parts: a cell plumbed into the return line and a control board at the equipment pad. As water flows through the cell, a low-voltage current across coated metal plates turns dissolved salt into chlorine. That chlorine sanitizes the pool, breaks down, and turns back into salt, so the salt gets reused instead of used up.

So a salt pool is still a chlorine pool. The difference is that chlorine is made steadily at the pad instead of poured from a jug or dissolved from tablets. Most systems call for roughly 3,000 to 3,500 ppm of salt, though the target varies by model, so go by your manual. That is about a tenth of the salt in seawater, which is why most swimmers barely taste it.

Salt does not evaporate. It leaves only with water that leaves the pool: splash-out, backwashing, draining, leaks, and overflow when a storm tops off the pool for you. After a run of heavy Gulf Coast rain, a low salt reading is often plain dilution rather than a failing system.

Hard water and scale: the main enemy of a salt cell

As a cell makes chlorine, the water right at the plates turns more alkaline, and calcium drops out as a white, crusty scale. Scale blocks the plates, cuts chlorine output, and can make the controller report low salt when the salt is actually fine.

Local water makes this a real issue, and it is not the same from one address to the next. Sugar Land publishes separate hardness ranges for its main system and for areas like Greatwood and New Territory, and Houston's report shows a similar spread depending on which plant serves you. Pools also concentrate hardness over time, because evaporation removes water but leaves the calcium behind, and every top-off adds more. Hot water and high pH speed up scaling even further.

Self-cleaning cells flip their polarity on a timer so the plates shed a thin layer of scale before it hardens. That slows buildup but does not stop it. One major manufacturer says that even with good chemistry, cells typically need cleaning three to four times a year. When scale does build up, the cell comes off for a short acid soak, and then we fix the pH and calcium that caused it. Steady weekly pool service is what keeps that from becoming a monthly chore.

The chemistry a salt pool still needs

A salt system handles chlorine production. Everything else is still on you or your pool company:

• pH. Salt cells push pH upward, so salt pools usually need acid added regularly to stay in the 7.2 to 7.8 range manufacturers call for. Holding pH down is the single best way to slow scale.
• Cyanuric acid (stabilizer). Houston sun burns off unprotected chlorine quickly, so outdoor salt pools still need stabilizer. Targets vary by cell model, so we follow your manufacturer's range, and free chlorine has to rise as stabilizer rises.
• Calcium hardness and alkalinity. Manufacturers commonly specify calcium hardness of 200 to 400 ppm and total alkalinity of 80 to 120 ppm.
• Phosphates. High phosphate levels can make chlorine hard to hold even with the cell turned up. One manufacturer lists under 200 ppb as a requirement.
• Salt itself. Use pure pool-grade salt, add it with the pump running, brush until it dissolves, and retest after a day of circulation before adding more.

Cold snaps, summer demand, and converting to salt

Salt cells protect themselves in cold water. Depending on the model, output scales back around 60 degrees and stops entirely near 50. During a Houston cold stretch the pool needs less chlorine anyway, but if the water stays below the cutoff for days, add chlorine by hand so the level does not bottom out.

Summer is the opposite. Hot water, heavy swimming, and afternoon storms that wash in debris all raise chlorine demand, and an undersized cell can run at full output and still fall behind. A cell rated above your pool's volume has headroom for those weeks, and pump run times have to be long enough for the cell to keep up. Tying the cell to a pool automation schedule makes that easier to manage.

Most chlorine pools can be converted to salt by adding a cell, a control board, and salt. Before converting, we look at your existing equipment and your deck and coping, since salt water can be hard on some natural stone. If you are still weighing it, our guide to salt vs. chlorine pools in Houston walks through the tradeoffs.

Signs your salt system needs service

• The controller shows a low salt, check cell, or inspect cell warning
• Chlorine stays low even with output turned all the way up
• You can see white crust on the cell plates or inside the cell housing
• The cell light is off or the board shows a no-flow error
• Salt reads low even though you have not drained, backwashed, or had heavy rain
• Your cell is several years old and output keeps dropping
• You are tired of buying, hauling, and storing chlorine

Salt system work we handle

• Salt chlorine generator installs on new or existing pads
• Converting traditional chlorine pools to salt
• Salt cell inspection and acid cleaning
• Salt cell replacement and control board diagnosis
• Flow switch and sensor troubleshooting
• Salt level testing and adjustment
• Full balancing: pH, alkalinity, calcium, stabilizer, and phosphates
• Output settings adjusted for summer heat and winter cold