Hayward AquaRite S3 and S3 Omni

The AquaRite S3 is Hayward's salt system with pool control built in. Besides making chlorine, it runs a variable-speed pump on up to three schedules a day, controls a heater, and turns chlorine down when an automatic cover closes.

It comes in three sizes, for 15,000, 25,000 and 40,000 gallons. The S3 Omni, in the 25 and 40 sizes, adds a separate Omni controller, relays for lights and other equipment, valve actuator outputs, and the OmniLogic app. A base S3 can be converted later with the AQRS3OMNIKIT.

The cell is the TurboCell S3, with a clear body so you can see scale and the bubbles of chlorine being made. The S3 won't run any other cell, and the older T-CELL range on the TurboCell page doesn't fit it. The Omni models run on the same OmniLogic app as Hayward's OmniLogic automation.

Which one

Pick the size by your pool's gallons. The manual gives each cell's output at 100%:

• AQRS315: 0.53 lb of chlorine a day, for pools to 15,000 gallons
• AQRS325 and AQRS325OMNI: 0.98 lb a day, to 25,000 gallons
• AQRS340 and AQRS340OMNI: 1.47 lb a day, to 40,000 gallons, or 25,000 on a commercial pool

The base S3 controls one pump, one heater and a cover switch from its own six-button display. It runs a Hayward variable-speed pump directly, a Pentair variable-speed pump through the HLPMPCONV converter, or a single-speed pump through an HLH485RELAY Smart Relay. Temperature sensors are sold separately, and it needs them for heater control and freeze protection. It can also run as a chlorinator only, taking its orders from a Hayward Omni control.

The S3 Omni adds two built-in high-voltage relays (three with a Smart Relay), two valve actuator outputs, control of up to two heaters, Wi-Fi and Ethernet, and inputs for pH and ORP sensors. Air and water sensors come in the box.

Converting a base S3 to Omni is a kit, not a new system. It adds the controller, an expansion board, the sensors and the relays. Hayward warns that every setting and schedule is lost in the upgrade, so write them down first. The controller mounts no more than 15 feet from the S3.

Installing it

• Mounting: vertical, knockouts down, at least 6 feet horizontally from the pool. The enclosure is vented, so don't block its sides or put it inside a panel. The cell, flow switch and sensor cables are all 15 feet.
• Plumbing: the cell and flow switch go in the return line, after all other equipment, in 2 inch PVC. The flow switch needs 12 inches of straight pipe before it, and its arrow has to point with the flow. On a pool and spa with spillover, the manual shows two layouts that chlorinate both during spillover without overdosing the spa on its own, and one layout never to use. Tighten the cell unions by hand.
• Power: 115 V at 2 A or 230 V at 1 A, which it detects on its own. If it controls the pump, it needs constant power. If not, wire it to the load side of the pump timer. In Canada, it goes on a Class A GFCI circuit.
• Last: plug the cell in after the front panel is back on.

The manual lists the variable-speed pumps that wire straight in as the TriStar VS 950 and 900, Super Pump VS 700 and MaxFlo VS 500. On a pump with dip switches, set them all off and disconnect the pump's own display. The TriStar VS page covers that pump.

For a heater, the S3 closes a low-voltage 2-wire remote contact. It doesn't switch the heater's power. The manual says the heater's own switch will very likely need to be on and its thermostat at maximum, and to use 105°C wire where the heater's manual gives no rating.

Salt

The base S3 manual says it makes chlorine from 1,200 to 8,000 ppm, with 3,200 optimal. Below that it keeps running in an alarm state down to 800 ppm, then shuts off. Its water chemistry table asks for 2,700 to 3,400 ppm, which the manual says stays below the level most people can taste. The low and high salt warnings default to 2,700 and 3,400.

The S3 Omni manuals give two modes instead. Standard Salt runs at 2,700 to 3,400 ppm, 3,200 optimal. Low Salt runs at 1,200 to 1,800 ppm, 1,500 optimal. You choose one when you set up the cell.

Use salt that's at least 99% sodium chloride: pool salt, food-grade salt or water softener salt. No rock salt, iodized salt, or salt with anti-caking additives. On new plaster, wait 10 to 14 days. Broadcast it with the pump on, brush it around, and run the pump for 24 hours. The salt reading can take that long to catch up.

For scale, Hayward's chart puts 267 lb of salt into 10,000 gallons of water with no salt in it to reach 3,200 ppm. The manual also says to check stabilizer whenever you check salt, since both drop with dilution, and gives a chart to bring it to 40 ppm. Hayward discourages dry acid for pH, because its by-products can build up and damage the cell. Saltwater pool maintenance covers the routine around it.

Setting the output

Chlorine output is a percentage from 0 to 100%, set with the + and − buttons on the home screen. It only makes chlorine while the pump runs, so longer run times need a lower setting and shorter ones a higher setting. Expect to raise it for hot weather, heavy use or an aging cell.

The water temperature at the cell decides whether it runs at all:

• 60°F to 140°F: your setting
• 50°F to 59°F: 20%, or your setting if that's lower
• Below 50°F or above 140°F: off

A heater upstream warms the water at the cell, so the display can read lower than the cell sees.

Super chlorinate runs the cell at maximum for the hours you choose. If the S3 controls the pump, it turns the pump on and overrides the schedule. If not, run the pump yourself the whole time. Turning the pump off, or turning the S3 off, ends it.

Cover detection needs a normally open switch from the cover. When the cover closes, output is capped at a setting you choose, and the pump can run at its own speed.

What the messages mean

From Hayward's technical training guide:

• Inspect Cell: comes up every 500 hours. Inspect the cell, then press OK to dismiss it.
• Cell Exhausted: the cell is past its service life.
• Cell Missing: the cable is unplugged, or the cable or connector is damaged.
• Invalid Cell: the cell isn't compatible, or it's defective. Try a known S3 cell or cable to tell a bad cell from a bad board.
• Output won't go above 20%: the water at the cell is cold.
• Output won't turn on: the chlorinator is disabled, flow is too low, the pump isn't running, the flow switch is unplugged or faulty, or the water at the cell is out of range.
• Time and date keep resetting: the guide blames the coin cell battery.

In freeze protection, super chlorinate pauses, and changing settings by hand means turning freeze protection off first.

Cleaning the cell

Turn the S3 off and take the cell out. Look for light, crusty scale on the plates. If there's none, put it back. If there is, try a high-pressure garden hose, then a plastic or wooden scraper. Never use metal, which scratches the coating off the plates.

For scale that won't come off, mix 4 parts water to 1 part muriatic acid: a gallon of water to a quart of acid, adding the acid to the water. Wear gloves and eye protection. The manual stands the cell in the solution with the wiring compartment above it, soaks it a few minutes and rinses it. The training guide pours the solution into the cell on Hayward's GLX-CELLSTAND instead. Repeat if scale remains.

Hayward's guide says cells kept at pH 7.2 to 7.8 with moderate calcium usually need cleaning three or four times a year. The Omni manual says to open and inspect the cell every 3 months or after cleaning the filter. Scale that keeps coming back points at the water, and the saturation index is where to look. If output stays low after a clean, a salt cell that won't make chlorine goes through the rest.

Winter and firmware

The cell and flow switch freeze like the rest of the plumbing, so drain them with the pump, filter and lines before a hard freeze. The manual says the control box can stay on the wall.

Firmware comes from the AquaRite S3 product page on Hayward's site. There are two files, for the display and the main board, and each is updated separately. The USB drive has to be FAT32, with the files in its root folder. The guide adds that some drives won't work, and that the system can take many seconds to find the drive, so don't rush the menus.

Buying one

All five are Expert Line systems sold through pool professionals, with three years parts and one year labor on Hayward's product pages. Hayward's brochure says they're only from pool pros, and its 2026 price schedule lists no online version.

An Amazon listing for the AQRS325 was selling at $2,199.95 from a third-party seller when checked, with a title claiming both 25,000 and 40,000 gallons. Hayward says its warranty applies only to products bought from Hayward or its authorized sellers, and that it can reject claims for products from unauthorized internet sites. For an Expert Line system, that's a real risk, so this page has no store link. How salt systems work covers the choice between brands.

Where Hayward's documents disagree

• Chlorine output. Hayward's product pages list 1.45 lb a day on all five systems and on the 15, 25 and 40 gallon S3 cells. The manuals give 0.53, 0.98 and 1.47 lb by cell. The 18,000 gallon cell's page says 0.6; the manuals say 0.73. The AquaTrol's pages give 0.75 for the system that cell fits.
• The salt range. The base manual says 1,200 to 8,000 ppm, alarming down to 800. The Omni manuals say 2,700 to 3,400, or 1,200 to 1,800 in Low Salt mode. The family brochure gives the S3 800 to 8,000 ppm, with reduced output below 2,700, and Hayward's sanitization brochure says the S3 Omni runs as low as 800.
• Cold and hot water. The manual limits output to 20% from 50°F to 59°F and shuts it off above 140°F. The training guide caps it at 20% at 60°F or below and shuts it off above 120°F. The Omni operation manual agrees with 50°F and 140°F.
• The flow switch. The manual lists it in the box. The training guide calls it sold separately.
• The battery. The manual says the coin cell battery is non-replaceable and not to attempt replacing it. The training guide's fix for a clock that won't keep time is to replace it.
• A part number. The manual lists the 25 ft flow switch as GLX-FLOW-RP-25. Hayward's site sells GLX-FLO-RP-25.
• Warranty. The product pages say three years parts and one year labor. The manual's warranty, still dated 2012, says three years and excludes labor. The family brochure advertises three or more years parts and labor from a Totally Hayward partner.
• The wrong quick guide. The 25,000 gallon product page links a quick reference guide for the older AquaRite, with a toggle switch, T-CELL sizes and a 2,400 ppm cutoff that don't apply to the S3.