Low Chlorine Solved: Troubleshoot Your Pool Chlorinator For Clear, Healthy Water
How Saltwater Chlorinators Work
Saltwater chlorinators produce chlorine automatically so you don’t have to add it to your pool manually. These systems use an electrolytic cell to sanitise your water. By adding a small amount of salt to your pool, the cell converts the salt (sodium chloride) into chlorine gas keeping your pool clean and safe. It’s a highly efficient and cost-effective way to maintain your pool’s water quality.
Understanding how your chlorinator converts salt into chlorine is the first step in troubleshooting. If this process is disrupted, chlorine production may drop or cease completely. Luckily, most issues are simple to fix. Read ahead for some simple troubleshooting options to try if you’re chlorine levels are consistantly low.
Salt Levels
Step 1: Check your salt level
This is important as different chlorinators require different levels of salt to produce chlorine. This can range anywhere between 900ppm-6,000ppm, so knowing the salt ppm required for your specific make and model of chlorinator is important.
- A salt level that is too low means that your chlorinator will not be able to convert salt into chlorine gas at a sufficient level.
- A salt level that is too high can cause damage to your chlorinator due to corrosion, in some cases causing the salt cell to overwork and shut itself down. If your salt levels are too high, the only way to reduce them is by partially draining the pool.
Salt test strips are available but in most cases you will need to have the salt level tested. At My Pool Shop Melbourne, we use a designated salt meter to accurately test the levels of salt in your pool or spa water.
Cleaning Your Salt Cell
Step 2: Check and clean the cell
One of the first steps you should take to troubleshoot your chlorine production is assessing the condition of the pool chlorinator cell. Over time, calcium can build up on the fins of your salt cell making it difficult to produce chlorine. Most modern chlorinators are self cleaning so you generally wont see a major build up but even a small build up can redcue chlorine production or trick the unit into thinking there is low water flow. If this happens the unit will often shut off the pump to protect it thinking there is no water flowing through it. And sometimes they malfunction causing a larger build up so it’s an important thing to check regularly.
If you see noticeable white scaling (calcification) on the fins of your salt cell, a 10-minute clean can make all the difference. Simply;
- Create a 1:10 acid solution (1 part acid to 10 parts water) in a sturdy bucket.
- Turn off your pool pump. If your equipment is below the waterline you will need to close valves or perhaps plug up your inlets and outlets if you don’t have valves.
- Remove the salt cell internals from the cell housing (the plastic cover) using a slights twisting motion for easy removal.
- Place the salt cell internals in the acid solution. You will hear some fizzing this is the acid dissolving the calcium. Do not leave your salt cell in the solution for longer than 10 minutes.
- If there is still calcification on your cell after 10 minutes, create a new solution and repeat the process until it’s clean.
No Flow
Your saltwater chlorinator relies on a steady flow of water to produce chlorine effectively. If the flow drops too low, the unit will display a ‘No Flow’ error as a built-in safety measure, shutting off the cell (and sometimes the pump) to prevent damage.
Common causes of reduced flow include clogged pump or skimmer baskets, dirty filters, or closed directional valves. Start by checking that all valves are open, the pump is running, and the sensor wire is properly connected to the cell.
Next, inspect the cell itself. Make sure it’s full of water and free from large air bubbles. The water must cover the flow sensor tab (connected to the blue lead inside the cell); if water isn’t passing over it, the unit will trigger a No Flow warning.
Keep in mind that a ‘No Flow’ error can sometimes indicate the cell is nearing the end of its life, especially if it has been in use for several years. In some cases, the chlorinator may temporarily switch off the pump to protect it from running dry, so always ensure there’s sufficient water in the cell before troubleshooting further.
No Power or Blank Display
If your chlorinator’s control panel has no lights or appears completely blank, it’s usually a sign that the unit isn’t receiving power. Start by switching off both the chlorinator and the power supply to the control box, then check that all wiring, including the mains supply and cell connections, is secure.
If these steps don’t restore power, or if a fuse is blown, the chlorinator will need to be assessed and repaired by a qualified pool technician to ensure it’s safe and working properly.
Possible End of Life
Pool chlorinator cells usually have a general life expectancy of 5-6 years, however this isn’t always the case. To test if your chlorinator is at the end of its life, try turning your chlorinator output to its highest setting and check if you can see any chlorine gas being produced and run for as long as possible. Before bringing in a water sample to re-test, don’t manually add any chlorine into the pool so that we can easily tell whether your chlorinator is producing any chlorine on its own.
Some chlorinators have a self diagnostic so we can assess if it is producing correctly but we would need to know the make and model to provide specific advice, generally a photo is all we need.
A tell tale sign that the cell if worn is degradation of the center plate like in the photo below. If you can see the edge of the plate has corroded while those either side are still intact, it’s usually time for a new cell.
Maintaining a healthy, sparkling pool doesn’t have to be complicated. By keeping an eye on salt levels, cleaning your cell, ensuring proper water flow, and checking your chlorinator’s power suply, most common issues can be quickly resolved. If you’ve tried these troubleshooting steps and your chlorinator is still not producing chlorine, it may be nearing the end of its life or need a professional check.
At My Pool Shop Melbourne, our friendly team can test your water, inspect your equipment, and guide you on the best next steps to keep your pool safe, clean, and ready to enjoy all year round, “because everyone deserves a healthy pool”.
