The Low TDS alert occurs when the TDS of the water is below 600ppm, indicating sanitisation will not be as effective as it would normally be. Another indicator of Low TDS will be that the OXI OUT reading will not retain its default setting of 100%. Ideal TDS levels for the Naked system are between 800-1200ppm. The alert is to warn you that the conductivity of the water has reduced and the system has lost the ability to adequately sanitise the pool. Please check the water balance regularly as prolonged Low TDS can damage the plate material of the cell and possibly void warranty.
Most often, low TDS is caused through dilution of the pool water such as recent rainfall or backwashing and topping up with fresh water. Other factors can include colder water temperature, not enough flow of water through the cell housing, which should be completely flooded with water while the system is operating or a build-up of calcium on the cell plate material which can also cause a drop in production.
You may also see this alert when starting the system the very first time on a new or renovated pool. If the TDS in the water hasn't had time to circulate throughout the pool, this message will appear however if the water balance is correct the alert will disappear once diluted.
Please refer to the attached Installation Guide which will show how to correctly balance the pool and get the TDS levels back to within range, more than likely salt is required to achieve this.
Depending on the size of your pool you may need to add 5-10 kg of fine pool salt in the shallow end of the pool and brush in when the pump is running and allow 30-60 mins for the salt to dilute.
You can use the calculators in the Naked app to determine how much salt is needed to restore the TDS to the correct level.