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Adding activated carbon to the resin tank of a water softener?

Posted by hanna256 (My Page) on
Tue, Feb 20, 07 at 17:05

I just met with someone who recommended adding 2 inches of granular activated carbon to the resin tank of a water softener to remove the chlorine from the water during the softening process. This would remove the need for a whole house inline water filter. The activated carbon would be backwashed at the same time as the resin and he said that the carbon and the resin would need to be replaced every 10 years.

This guy works for a major water treatment company but I have never heard this recommendation before, nor have I found any info on on the Internet. Any opinions on this?


Follow-Up Postings:

RE: Adding activated carbon to the resin tank of a water softener

My opinion (as a former water treatment professional) - this is stupid. Most water treatment companies hire good salespeople - NOT good water chemistry people. True, the carbon would be backwashed with the resin, but it certainly wouldn't be regenerated with the resin and would be totally useless after a few months. Further, your softener bed is designed to be a certain depth and adding 2 inches to the top of it can mess up your flow as well as the effectiveness of the backwash. You will end up either losing the carbon or losing part of the resin bed. Bad, bad, bad idea.

You can go one of two ways: Cartridge filters, which are cheaper to purchase (around $100), but require that you changed the cartridges every 12 months (around $40 for replacement cartridge), or a cylinder that looks much like your softener ($500 - $800) and would backwash periodically, requiring extra plumbing. You would replace the carbon every whenever it quite removing the chlorine. The amount of time would depend upon the level of chlorine in your water, as well as the general quality of your water, but could be 5 years or 20 years. Generally, I would recommend the cartridge filters because they are easy to install and maintain, take up little space, and require minimal knowledge on the part of the home-owner.

RE: Adding activated carbon to the resin tank of a water softener

Thanks for the info. But I am curious how the carbon is reactivated in the carbon cylinder that backwashed regularly?

The guy was saying that is the way the culligan 3 in 1 water softner/water purifier works - resin and carbon is the same tank that backwashes regularly.

As for the cartridge filters, the one I saw needs the filter changed every 2 to 3 months and the filter is about 30 to 40$. Which filters last 12 months? I looked at the 10" filters.


RE: Adding activated carbon to the resin tank of a water softener

I agree that carbon and resins should not be mixed. They are basically the same specific gravity and will blend during backwashings. The advantage of removing chlorine to protect the resins is soon lost.

Moreover, the resins are hard and the carbon brittle. The resin will grind the carbon into fines and they will be backwashed out every time it regenerates. There is usually little need to 'replace' carbon as it is mostly gone, depleted.

Unless your softener was under some unusual stress, there should be no reason to replace your resin every ten years! Sounds like maintenance marketing to me.

For very effective chlorine removal, use a granulated activated carbon (GAC) with a KDF-55 be in a refillable cartridge prior to you softener. The KDF will last a very long time and give your carbon an opportunity to do other jobs like odor control.

I hope this helped,

Andy Christensen

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