Can You Mix Water Softener & Filter Technology?
The idea of solving multiple problems with one water treatment system is appealing.
The problem is, not all medias used in water treatment are the same.
Water Softening Resin and Carbon are fairly similar in operation, while others are completely different.
You have to treat each media according to manufacturer’s specifications. Otherwise, the media will fail, and the system will collapse.
Weight Matters
A lot of water treatment terminology is industry specific. It’s confusing. So lets start with something easy to compare.
Look at the difference in density between these filter medias:
| Water Treatment Media | Pounds per Cubic Foot |
|---|---|
| Coconut Shell Carbon | 31lbs/ft3 |
| Water Softener Resin | 50lbs/ft3 |
| KDF | 171lbs/ft3 |
Keeping it Clean
All filter media must be periodically backwashed. A backwash is a forceful flush, up through the media. It is REQUIRED to scrub the media clean with water.
If media is not backwashed correctly, it becomes ineffective.
The heavier the media, the more water it takes to clean it out.
Lets compare the gallons per minute (GPM) required to flush out carbon and KDF:
| Water Treatment Media | Backwash Rate in GPM |
|---|---|
| Coconut Shell Carbon | 10gpm/ft2 |
| KDF | 30lbs/ft2 |
It takes 3x more water to backwash KDF than carbon!
Lets see what this would mean in a system with a 10” diameter tank. A 10” tank has roughly 0.55 square feet (ft2) of surface area.
5.5gpm required to flush out a 10” carbon filter
16.5gpm required to flush out a 10” KDF filter
What This Means to You
If you mix KDF and Carbon in the same system you have to make a choice:
- Use a high backwash to maintain KDF, but blow all the carbon down the drain the first time the system regenerates
- Use a lighter backwash for Carbon, but accept that the KDF will be useless in a matter of weeks or months
As you can see, that just doesn’t work.
You can successfully combine friendly media like water softening resin and carbon in a single tank. They can be adequately backwashed as they are closer in spec. This will keep each media clean for years of high quality water.
How We Can Help
Premier Water Technologies offers dedicated water softeners, carbon filters, reverse osmosis, and a variety of specialized technologies.
Our DMT Hybrid Dual Media System combines softening and filtration in a single unit. This protects your home from hard water damage, but also filtered drinking water and protection from chlorine and chemicals.
Solving multiple problems with 1 unit can work – IF the system is designed correctly.
Call us at (952) 767-0230, or sign up for a FREE WATER TEST to find the right system for your water!
I have a 9″x 48″ tank with coconut shell media with proper back flow valve. This system has worked fine for years but the bacterial iron has increased and I want to add KDF85 to this system. How many pounds do I add? Do I need to remove any coconut shell first? About a coffee can of shell spilled out when installed some years ago. Do I need to reset my backwash timer to something different? Will appreciate any assistance who can offer. Thanks
I would not mix carbon and KDF. They have totally different densities and operate completely differently.
Thanks for posting!