McAlpine SCA-RE Scale Defender Refill Cartridges (X2)

The dosing filter capacity is a maximum of 40,000 litres and should be replaced when exhausted to maintain the effectiveness of protection. Inside the dosing filter is a small red ball. When the ball is at the bottom of the dosing filter, the filter should be replaced. We recommend checking the filter every month or so. The pre-filter can be checked and cleaned periodically, or upon changing the dosing cartridge to ensure the flow rate through the system is not reduced. This may vary depending upon your water conditions.