One 5 pound bag is enough for 4 refills of our 10" refillable cartridge

indicated by a blinking 'x10' image

RO systems

9% rejection rate membranes combine 5 heavy duty stages of filtration

Your meter will be perfectly fine and the small extra bottle is included for this purpose

HM Digital TRM-1: Triple Inline TDS Monitor Membranes One 5 pound bag isThe TRM 1 is a unique monitor offering the user 3 points of contact during the filtration process. This TDS monitor allows for checking TDS levels at 3 points, such as with DI RO (deionization reverse osmosis), multiple points in an RO system, and more. FEATURES Displays TDS levels of the three sensing points with electrode probes Highly efficient and accurate due to its advanced microprocessor technology Auto Off function conserves battery power. The