Circupool SWG - Further Reading

Circupool SWG

Circupool is a popular SWG brand due to their competitive pricing and warranty allowing DIY installation. Reports are they also have good tech support and the office is staffed by cordial, friendly people.

Note all gallons and chlorine output below assume the cell is running at 100% 24/7.

Circupool may include a sticker that says "10 PSI max". That is not your filter pressure. They are talking about a differential pressure between the input to the cell and the output of the cell. Since one side of the cell is basically the pool, you will not see anything close to 10 lbs. The only situation where the pressure in a cell would be higher than 10 psi is if you have an in-floor cleaning system.

CircuPool CORE CONTROL

Circupool released the CircuPool CORE CONTROL in March 2025. The Core Control is a modular system that includes a control unit, WiFi module, app control, and a SWG cell. An ORP/pH monitoring module for chemical automation is expected in Summer 2025 and pool system automation and equipment control is expected in 2026.

Circupool Core Control 55 Initial Thoughts describes one of the first member installs.

SJ Series

• The SJ is a basic model with only 25% increments for % generation. That may not provide fine enough % control if you get an oversize cell. You will need to use runtime to make finer adjustments to cell chlorine output.
• The SJ series cell must be mounted horizontally and 6" above the highest plumbing point, which limits installation options. The design and positioning of the cell allows for air pockets to form on the top portion of the cell, exposing the plates, particularly when running at lower speeds.

SJ Models

• SJ15 - 15,000 gallons - 0.65 lbs/day Chlorine
• SJ20 - 20,000 gallons - 0.87 lbs/day Chlorine
• SJ40 - 40,000 gallons - 1.60 lbs/day Chlorine
• SJ55 - 55,000 gallons - 2.30 lbs/day Chlorine

RJ Plus Series

• The RJ has more precise % increments of 5% than the SJ series increments of 25%
• The RJ cell with unions is 15 ¾” in length, and the Flow Switch is 4” in length
• The RJ comes with 1 1/2" and 2" unions and 2"-to-1 ½" reducer bushings to adapt the Flow Switch
• Circupool has a Vertical Installation Kit. The typical gap required for installation with the Vertical Installation Kit is 6.5 inches.

RJ Plus Models

• RJ16+ - 15,000 gallons - 0.70 lbs/day Chlorine
• RJ20+ - 20,000 gallons - 0.90 lbs/day Chlorine
• RJ30+ - 30,000 gallons - 1.50 lbs/day Chlorine
• RJ45+ - 40,000 gallons - 2.00 lbs/day Chlorine
• RJ60+ - 60,000 gallons - 3.10 lbs/day Chlorine

Extending the RJ+ Power Cord

The CircuPool RJ+ units come with a power cord that is about 48 inches long. If you need to replace the cord with a longer cord see the Installing a longer power cord in a CircuPool RJ+ thread.

RJ+ Features

• When installing the RJ45+, according to the manual, the average salinity will read what was measured at the factory. It takes 24 hours of pool operation for the average to update.
• If you get low salt and low flow red lights try rotating the cell with the offset down
• Blinking flow indicator may be caused by a power interruption.
• The RJ series stops generating when water temperature is below 60 degrees. A member reports that the got various TEMP messages during the winter and when the water temperature got into the 70s the cell did not automatically begin generating. He had to press the On/Off toggle button to turn the CircuPool SWG to off and back on to get it reset and generating chlorine. We recommend turning the SWG off when water temperature drops below 60F during the winter.
• If the control unit doesn't clear faults by being switched off turn the circuit breaker Off and On.
• When the generating light is off, that means it's in the off portion of the cycle and it will not show salinity. Salinity will be displayed only when the generating light is green. You can always bump up the percentage momentarily and it'll turn on. At that point you will have a choice to see the average or the actual salinity. It has to generate for a few minutes before any of the salinity info there is meaningful.
• The RJ60+ control box has an internal fan that sometimes fails.

Circupool RJ Plus 10 PSI Limitation

RJ Plus Cells now have a label that says "Maximum 10 PSI - Avoid over-pressurization of this device!"

The filter pressure PSI is not the correct measure of PSI at the SWG cell.

The PSI warning relates to pressure at the salt cell, down-stream of the filter where the typical pressure is 1-3 lbs. The water at the cell is flowing directly into the pool with very little resistance. It has nothing to do with the pressure on the filter gauge, upstream of the filter media and heaters and naturally quite a bit higher.

The purpose of the warning is to avoid the closure of any valves that may be after the salt cell, such as diverter valves for spas, waterfalls, etc. that can raise pressure at the SWG cell.

Pools with an IFCS (In Floor Cleaning System) can have return output pressures of 15-20 PSI and exceed Circupool's warning. Some members with Circupool SWG and IFCS have said they have not had a problem. Or you may want to consider a different SWG that does not have a PSI limitation if you have an IFCS.

In this post a member has confirmed with Circupool that normal operating PSIs inside the salt cells of up to 20PSI (due to IFCS) will NOT invalidate any warranty.

RJ45+ High Water Temperature Error

The RJ45+, and maybe the other RJ cells, have the water temperature sensor in the cell. Members have had the system begin giving a High Temp error.

The board has a jumper that will change the temperature sensor from the cell to the flow switch. If your flow switch does not have a temperature sensor the system will default to 77F and the salinity calculation will be a bit off.

Replacing the flow switch with a combination flow switch and temperature sensor will restore the proper temperature sensing and salinity calculations. One simple way to tell if your flow switch has the temperature sensor or not is the thickness of the wire.

RJ60 Low Temperature Shutdown Not Resetting

A member reports that his RJ60+ runs fine in the daytime, but overnight the current pump cycle turns completely off for about 6 hours and the water temp in the piping gets into the 40s/50s. The RJ60 throws a low temp error as expected, but once the temps warm up back into the 60s, the low temp error stays and the system won't run.

He spoke with a person at DSP and was told that once the low temp flag is set the unit will not self-recover and the power must be cycled to reset it.

If you have your SWG connected to a timer so the SWG is powered off when the pump is off, as TFP recommends for safety, you should not see this problem unless the pool water is cold when your pump and SWG turns on.

RJ-60+ Cell Not Match

Discount Salt Pools will send you a PCB Adapter to fix the error.

This Thread has a copy of the PCB Adapter installation instructions.

RJ Fan Replacement

The fan in the Circupool RJ SWGs has been known to fail. The fan is 40x40x20mm 24V DC Brushless Fan with 4 screw holes, one in each corner and mounted to a sheet metal plate.

A 2-pack of fans can be found on Amazon.

RJ-60+ Cell Connection Error

Circupool has a published Cell Connection Troubleshooting guide that can be found here:

Cell Connection Troubleshooting

Diagnostics

Menu: Press sequentially to cycle through the following information:​

1. Pool Temperature (xx degrees Fahrenheit or Celsius)​
2. Cell Voltage (often 21.0 to 27.0 volts when chlorine is being generated, otherwise 16-31V)​
3. Cell Current (often 2.50 to 7.80 amps when chlorine is being generated, otherwise 0 amps during normal rest cycles.)​
4. Real-Time Salinity reading ( xxxx PPM or x.x grams/Liter.)​
5. System ID​
6. Software revision level​
7. Cell Version.​

Circupool RJ Series Salinity

Discount Salt pools has said the following:

Like the Hayward, the Rj System measures salinity by determining the level of conductivity in the water. Anything that affects conductivity can trigger a low salt/check cell indicator. Some examples include low salt, dirty cell, air trapped in the cell or low water temperature. All of these things must be aligned in order for the system to calculate an estimated salinity level. Also, ensure 'cell type' setting has not been changed. Customers often unknowingly change the cell type altering the salinity level which in turn can also trigger a warning light. Any solid warning lights will shut off amps to the cell, meaning no chlorine production.

They recommend going through the items on this page before replacing the cell.

CORE Series

• The CORE is an all-in-one unit that integrates the controller and flow switch into one component for easier installation. Like the SJ series, it provides 25% increments for % generation. Finer adjustment of output needs to be done by adjusting pump run time.

Core Models

• CORE-15 - 15,000 gallons - 0.90 lbs/day Chlorine
• CORE-35 - 35,000 gallons - 1.40 lbs/day Chlorine
• CORE-55 - 55,000 gallons - 2.30 lbs/day Chlorine

Core Features

• You cannot rotate the control head as the cell can only plug in one direction to the controller.
• The cell also has to be inserted the same other way as it is keyed to its housing.
• The flow direction is bi-directional, as the flow switch activates either way.
• It will automatically recognize 100 to 240vac up to 4 amps.
• The Core-55 has eight flow channels where the water flows over the many plates.
• The flow sensor is built in, so there is no separate sensor to install.
• The cell is transparent to see the water flow and hydrogen gas being generated to ensure the unit is working.
• The Core series does not have a lot of the display features and diagnostics that other units have.

Core LED Lights

• NO FLOW: When this LED is illuminated, the system detected insufficient water flow through the Cell, which causes the Cell to stop generating chlorine. Verify that you have proper water flow without air bubbles in the Cell housing and that the water flow fully moves the flow switch away from its resting center position. Clean your filter and increase flow if you have a variable-speed pump until the LED turns off.
• LOW SALT: When this LED is illuminated, salt may need to be added to the pool. First, check the salinity of the pool water using a salt test meter or Taylor K-1766 Salt Test Kit and add salt if the level is low. If this does not solve the problem, inspect the Cell for mineral scaling and clean it if necessary.
• COLD WATER / WINTER MODE: To protect the Cell, the Control Module is programmed to decrease chlorine production when it senses low temperatures automatically. In case of low water temperature below 64°F, the unit reduces chlorine production to 50%, and the LED below the 50% bar will be lit. Below 59°F, the unit reduces chlorine production to 25%, and the LED below the 25% bar will be lit. In both cases, the LED below the required level bar will blink, and the "Cold Water" warning LED will be illuminated.
• CLEAN CELL: When this LED is illuminated, it indicates that the Cell requires cleaning. Refer to How to Clean a SWG Cell before following Circupool Instructions to do an acid bath.
• CELL LIFE LOW: This LED is illuminated when the Cell is likely reaching the end of its expected lifespan.
• SYSTEM ERROR: This LED illuminates when the system cannot produce chlorine. Please refer to the “Troubleshooting” section on page 18 of the Circupool Core Installation and Operation Guide.

EDGE Series

The Edge Series has a simple display using LEDs to show % output and other cell status.

EDGE Models

• EDGE15 - 7,500 to 15,000 gallon pools - 0.70 lbs/day Chlorine
• EDGE25 - 17,500 to 25,000 gallon pools - 1.20 lbs/day Chlorine
• EDGE40 - 30,000 to 40,000 gallon pools - 1.7 lbs/day Chlorine

EDGE Features

• The Edge has LED lights to give you information
• SWG % adjustment is in 12.5% increments
• When you set it to 50% it runs at 50% power and does not cycle at 100% for half the time and then off like most other US SWGs
• There is a separate flow switch to be mounted before the cell
• The Edge doesn’t have an internal fan
• The Control Module is a separate unit that can be placed in a bit more controlled environment then the CORE Series.

Circupool Edge Union Leaks

Members are finding a union may have a loose fit and leak or pop off when tightened.

The fix discussed in Circupool Edge union leaks has been to put a 4" worm hose clamp around the union to compress it and create a tighter fit around the threads.

Circupool Vertical Installation

Circupool has a Vertical Installation Kit if you need it.

Should the Circupool Cell be Acid Cleaned?

We discourage routine acid cleaning of SWG cells unless other less damaging methods fail to remove scale. SWG How It Works discusses alternate ways to clean a cell before you should use acid.

Cirupool, AR-Pro and others sell similar cleaning stands that cap one end of the cell and lets you pour cleaning solution in to soak the plates.

ALWAYS add acid to the water, NEVER add water to the acid. Always wear eye protection and use rubber gloves. Always work in a well-ventilated area.

Circupool SWG Maintenance Tips

Keep Control Panel Out Of the Weather

Circupool customer support recommends having a roof or shelter over the control. Even though it's designed to be outside and is "waterproof". They say if you want longevity with control keep it out of the elements, direct sun and rain.

Air builds up in SWG cell

• Check cell is level
• Check filter pressure and flow. Backwash filter.
• Put the hump down to help clear out any air from the cell.

Bubbles Around the Plates

• SWGs generate chlorine gas and hydrogen gas. The chlorine gas dissolves pretty quickly in the water. Hydrogen gas does not dissolve as much. So, if you're watching the returns, you should only see hydrogen gas. If you're watching the plates through clear cell walls, you can see chlorine gas being generated.
• The bubbles on both sides of the center plate are hydrogen or chlorine depending on the polarity.
• Bubbles form on the inner walls of the outer plates but not on the outer walls of the outer plates. The bubbles on the center plate are the opposite of the bubbles on the inner walls of the outer plates.
• Hydrogen gas and chlorine gas are both generated at the surface of the plates.
• Hydrogen gas is seen as bubbles on one side of the plates and chlorine gas is seen as bubbles on the other side of the same plate.
• The size of the bubbles is partly dictated by the water flow.
• Higher flow means smaller bubbles.

What Causes SWG Cells to Explode?

• SWG's have an explosion risk if the cell is powered and generating when there is no water flow. This can be caused to a stuck flow switch.
• When a cell explodes, it's due to the combined chlorine and hydrogen gasses.
• Hydrogen gas needs an oxidizer to burn. Usually, the oxidizer is oxygen, but there's no oxygen available.
• There's no oxygen, but the chlorine is a better oxidizer than oxygen and produces a faster reaction.

Circupool Universal 40 Humming / Whirring Sound

The Universal 40 and maybe other models have a fan inside. The sound corresponds to the fan spinning up and slowing down and the sound appeared to be coming from the fan. Removing the 4 screws holding the fan in place and turning it back on quieted the sound.

The fan is mounted to the housing over a vent to external air with a mesh screen 'sandwiched' between the fan and vent opening. The mesh screen became loose over time and the fan blades were rubbing against the mesh screen.

If you remount the fan with the 4 screws and back-off 2 of the screws a quarter turn and that can be enough to prevent the sound.

Circupool Support and Warranty

Some members have had issues contacting Circupool by phone and email, but have found good response using the "Additional Help" contact form at the bottom of This Circupool Contact US page