Salt Water Pools: Still Chlorine, With Different Upkeep

Applies to: Home pools with a salt chlorine generator. Examples come from Hayward's AquaRite and Pentair's IntelliChlor manuals; other systems differ, so check your own manual.

How a salt chlorine generator works

Hayward's AquaRite manual says the unit converts salt into free chlorine, which kills bacteria and algae and then reverts to salt. Pentair's IntelliChlor guide describes the same idea using electrolysis.^[1][2]

The generator does not do your testing. Pentair's guide says the unit does not monitor or control chlorine levels, and that it is the owner's job to check free chlorine regularly while the pump runs.^[2]

Salt level: your manual sets the number

• Hayward AquaRite: ideal salt is 2700–3400 ppm, with 3200 ppm optimal. Low salt lowers chlorine production, and high salt can shut the unit down.^[1]
• Pentair IntelliChlor: 3600 ppm is recommended. Below 2600 ppm the unit turns off, and above 4500 ppm it may cause excess corrosion.^[2]

Test before you add salt. Pentair says owners must always test first and that its built-in sensor reads within plus or minus 500 ppm. Hayward suggests a professional salt check before adding large amounts.^[1][2]

Salt does not evaporate. Hayward says it is lost through splashing, backwashing and draining, and the only way to lower it is to partially drain and refill. Draining can damage some pools: Latham says a vinyl liner can shrink and crack if the pool is completely emptied, and its fiberglass pools are designed to stay full, so check with your pool's maker or a professional first.^[1][3][4]

Use the salt your manual specifies. Both manuals rule out certain kinds, including rock salt and salt with anti-caking additives, and Pentair says some additives can discolor fittings and surface finishes.^[1][2]

Stabilizer and pH still matter

Hayward says outdoor pools should check stabilizer whenever they check salt. Pentair says cyanuric acid is needed outdoors, should be kept at 30–50 ppm with its system, and should not be used in indoor pools.^[1][2]

A fiberglass pool maker, River Pools, notes that salt systems make pH rise gradually, so test often.^[5]

Both manuals discourage dry acid (sodium bisulfate) for lowering pH, especially in dry climates. Hayward says it can leave by-products that damage the cell.^[1][2]

Cell care: inspect, and follow the manual exactly

• Hayward recommends opening and inspecting the cell every 3 months or after you clean the filter.^[1]
• Pentair's cell reverses its blades every few hours to help keep itself clean. If scale tends to form, Pentair recommends checking it every two months, and at least twice a year in any case.^[2]
• Turn off the power before you remove a cell. Hayward says to use a plastic or wood tool, never metal, for scraping deposits.^[1]
• Both manuals start with a strong hose rinse and describe acid cleaning only when deposits will not come off otherwise. Pentair warns that muriatic acid can be dangerous and that too much acid washing damages the blades.^[1][2]

What differs from system to system

• Cold water: Hayward's unit stops making chlorine below 50ºF, and Pentair's at about 52°F. Hayward advises checking chlorine in cold weather to avoid over-chlorinating.^[1][2]
• Covers and liners: Pentair's guide says that when its IntelliChlor is used with covered pools or vinyl liner pools, less chlorine is needed.^[2]
• Pool type: Pentair's IntelliChlor is not for storable or steel pools. Use equipment rated for your pool.^[2]
• New surfaces: before adding salt, Hayward says wait 10–14 days on new plaster, Pentair says at least one month, and the finish maker Pebble Tec says at least 28 days for its finishes. For new vinyl liners, Pentair says to contact the liner maker.^[1][2][9]
• Freezing climates: both manuals say freezing water can damage the cell. Hayward describes draining the pump, filter and lines before freezing weather. Pentair describes either running the pump continuously or draining the equipment and removing, cleaning and storing the cell. What fits depends on your climate and system, so follow your own manual.^[1][2]
• Spring: Hayward says not to turn the unit on until the water chemistry is at proper levels.^[1]

Salt is corrosive. Pentair says it cannot guarantee its system prevents corrosion of equipment and surfaces, and Hayward advises consulting a qualified stone specialist about natural stone coping or decking.^[1][2]

Electrical safety and when to call a professional