Replacement water filters, RO reverse osmosis membranes and whole house filter systems. Refrigerator water filters, pool and spa filter. Pentek, OMNIFILTER water filters. Chiller Daddy water chillers

Easy TDS Membrane Performence Calculator
See If It is Time To Replace Your Membrane

Simply enter your Feed Water TDS and RO Water TDS into the boxes above and click "Submit". The percentage of TDS (total disolved solids) rejection will be displayed. We normally recommend membrane replacement once you drop below 75%. This may vary in areas with high TDS in the feed water.   Let the tap water and reverse osmosis water run for a few seconds before drawing your sample.

See our selection of TDS meters under Water Tests.  Knowing the rejection rate is the only wat to know if it is time to replace your reverse osmosis membrane.


Be sure to check our Parts Department for important parts such as TDS Testers For Reverse Osmosis Membranes, Replacement Tanks, O-rings , Filter Housing Wrenches, Faucets, Pumps, Fittings, UV Systems and more parts for your reverse osmosis pure water filtration system.   View maintenance and servicing tips online at our Installation & Trouble shooting Guide.


* Aquacheck ® is the registered trademark of Aquacheck, the manufacturer of Aquacheck ® brand water treatment equipment.  The replacement filters and membranes listed above are not manufactured or endorsed by Aquacheck.  Rather, these filters and membranes are manufactured by other companies.  While these filters and membranes are compatible for use in Aquacheck ® brand water treatment equipment, we make no representation as to whether using these filters and membranes is consistent with the warranty and specifications applicable to Aquacheck ® equipment.