View Full Version : Which cartridge need to replace?

04/07/2017, 11:55 AM
I have four stages Aquatic-life delux 100GPD unit. My city water come in at 350ppm reading on the TDS meter, water come out after filter is 24ppm (Sediment filter, carbon, DI and membrane). I also have BRS Dual Deionization canister after Aquatic-life delux that bring down to 6ppm on TDS meter. Which cartridge should I replace now?
Btw, I just order a MATRIKX 5 STAGE RO/DI REPLACEMENT FILTER KIT and 75GPD membrane. Should I repalce them all or just replace what I need to replace?
Thank you for helping.

04/07/2017, 02:33 PM
Hey there!

Unfortunately, you cannot determine what exact filter to replace by TDS alone. Really the only two filters for which TDS is an indicator is the RO membrane itself and the DI Resin.

Typically RO membranes can last up to 2-3 years, so over the course of that time if you are typically running at 24ppm after the membrane and you start to notice that number steadily climb during each usage; that is an indication that the membrane is becoming exhausted and may need changed soon.

DI resin operates in the same manner, where as it becomes increasingly exhausted the output TDS will continue to rise. One concern I do see with what you have explained is that you have 24ppm before the DI and 6ppm afterwards. A dual DI canister should easily be able to bring the 24ppm down to 0ppm upon a fresh resin change. Granted, 24ppm is VERY high and will cause you to use DI resin much faster, but 6ppm is still pretty high for an output. I typically don't use water above 2ppm unless it was an emergency.

We actually did a video in the last few months about filter indicators that might help you out a bit further! Check it out below. :)