Using water softener to reduce CH?

[lovingHDTV]

What if you were to install a water softener into the pool plumbing, then when the CH gets too high, you run a couple batches of water through the softener to remove the CH. I could then see that if you also ran your auto filler through the softener you should be able to stay on top of the CH issues.

Has anyone done this? I know that you can't use a home softener to reduce the whole pool at once due to capacity issues, but you could do it incrementally. then keep on top of it.

For <$800 it seems like it may not be a bad thing. Of course it would be nice if you could just measure the hardness and turn on the softener when needed. With the flow meeter the softener it would know when to recharge and all.

What I don't know, is the effect of the chlorine, borates, etc on the resins in the softener.

Comments?

 

[chem geek]

Unless you use Cal-Hypo for chlorine or otherwise add Calcium Hardness Increaser (i.e. calcium chloride), the CH in the pool will only rise from the fill water. So once the CH is at the level you want in a pool, you should only need to attach a water softener to the fill water inlet line. With 0.5" evaporation per day which would be higher than normal even in the hottest areas, for a 16'x32' pool that's 160 gallons which isn't too much to filter per day. Of course, one has to add to that any splash-out or backwashing amount.

As for filtering existing pool water, some filters use activated carbon that will remove chlorine from the water. Some of the softeners, using an ion exchange resin, will replace calcium and magnesium with another salt, either sodium or potassium, but since pool water can already be salty, they might not work very efficiently (especially in an SWG pool) if the water softener uses sodium salt. Reverse osmosis systems will remove almost everything so will remove chloride as well. You probably need to check with the manufacturer and give them your numbers and tell them what you are doing to be sure even with the ion exchange resin water softener which sounds like the one you would need.

Richard

 

[JasonLion]

There are a couple of things to keep in mind with standard water softeners. They are designed for fairly low flow rates compared to the size of a swimming pool, 5 to 10 GPM max, and several hundred gallons a day max. Every couple of hundred gallons of water they need a regeneration cycle, which takes an hour or two and dumps 20 to 50 gallons of water down the drain.

 

[TomU]

Keep in mind too that chlorine will destroy the resin in a standard ion exchange water softener. There are other resins one can use that are more resistant, but this is still only for very low levels of chlorine. The low levels of chlorine in city water will typically destroy the resin in a softener in about 10 years. Its common to get 20 years or more from the resin in a softener running on well water. In fact, usually its not the resin that wears out in these situations, but the mechanical components of the softener.

 

[chem geek]

City water that used to use chlorine instead of monochloramine had around 1 ppm FC with no CYA. This is far, far higher in "active" chlorine (hypochlorous acid) concentration than in pools which have the equivalent of 0.1 ppm FC so I'm not so sure the resin will get destroyed that quickly with pool water unless the destruction has to do with the capacity of chlorine rather than reaction rates (and I doubt it has to do with capacity since water flows through the system so reaction rates should be what matters in terms of breakdown of resin). I would agree that a pool with no CYA in the water and > 1 ppm FC would be more harsh on the resin.

Remember that FC does not actually measure active chlorine, but mostly measures the chlorine that is in reserve.

 

[lovingHDTV]

I thing that I found recently is that you can get water softener that use Zeolite. I believe that is the same thing used in my pool filter. That got me thinking so I looked and they do talk about doing a "recharge" of the Zeolite media by soaking it in salt water, then pumping to waste. They say this will then allow the filter material to remove calcium from the pool water.

Maybe a Zeolite based softener would work better. I'll make a call and find out about reduced efficiency if the salt ppms approach 3500. I did not think about that.

http://home.howstuffworks.com/question99.htm

 

[SPP]

Hello HDTV,

My Zelbrite manufacturer said that SWG salt level is not enough to regenerate the zeolite.
I am assuming your zeobrite would be the same.
The regenerate level is 10% of salt in water , which is way much higher than 3,500ppm.


EDIT --
I am now waiting for them to answer me some questions, maybe you can ask your zeobrite manufacturer too.
I ask since the type of zeolite we have is cr???? something, I forgot the spelling. It is supposed to consist of calcium, magnesium and sodium ions and it loves ammonia. I asked them, how much love does it have for calcium ?.. and what are the percentage breakdown of those those 3.

I am just curious if it can be renegrated by an "X" level of salt, what is the CH level in water that will cause my calcium in my water get trapped by zeolite ...if indeed it will trap calcium ? -- EDIT


Thanks