Water Softener Regeneration Qestion

[FoxRox]

I am trying to figure out if it is possible to "tune" a water softener to produce less brine when it regenerates by sacrificing some of the effectiveness.

When a water softener regenerates, what is target "completion" for backwashing out all the calcium and magnesium ions? 100%? 99%? 90%? Do water softeners use more brine than necessary to get close to 100% ion exchange?

If the regeneration does not go to completion every time, would that have some negative long-term effect on the resin, or would it just reduce the effectiveness of the softener?

What does the curve of sodium ions vs hard water ions in the resin look like throughout a regeneration? Do most of the hard water ions get backwashed quickly and then the last few take a long time? i.e. Are there diminishing returns as the regeneration continues, or is it close to linear?

With my limited understanding of the chemistry, I hypothesize that you could use half the brine but still get more than half of the ions (hopefully a lot more than half). Additionally, the discharge itself would be less salty due to significant ion exchange occurring for the full duration of the regeneration cycle, rather than the tail end of the cycle being near 100% brine (if my hypothesis is correct).

Are there softeners out there that let you tweak settings like this, or is the amount of brine used always set from the factory and not adjustable?

Just for some background, I am trying to solve a problem where softener backwash is negatively affecting the performance of a septic tank. I can provide more details on that if someone wants to hear, but my primary question is about limiting brine discharge while still getting acceptable performance. Is there a tradeoff to be made, or am I completely off base with this idea?

 

[EdStainless]

How old is this softener?
If it is more than a few years old, then it likely doesn't use current technology.
Does it actually meter water usage to determine when to regen?
Does it use a 'dry' brine tank, does it make brine for each recharge.
When I replaced mine 5 years ago my salt usage dropped to 1/5 of what it had been.
The old unit didn't flush to the septic, the new one does.

You could start trimming the amount of brine used and see how much faster the water becomes unacceptably hard.
You should also look at the backwash and see if it is excessive.

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P.E. Metallurgy, consulting work welcomed

 

[FoxRox]

Thanks for the reply.

The house is only eight years old, but I just bought it last year. I don't believe the softener was installed initially, but I don't know exactly when it was. Either way, it cannot be too old. It is a Sterling NES Series if that tells you anything.

The softener does regen based on water usage (currently set at every 400 gallons).

I am not exactly sure what you mean by "dry brine tank". It has a bin that you fill with salt. It does not stay full of water, but it does stay wet at the bottom.

You could start trimming the amount of brine used

I don't believe I can. This is part of my question. There does not appear to be the option reduce the amount of brine used on my softener, unless I am missing it somewhere in the manual. Do other softeners have this option?

 

[EdStainless]

Yes, that is what is often called a 'dry' brine tank in that it doesn't store brine.
Some have those settings and some don't.
On mine I can set length or amount of regen (salt use) and I can set the backwash.
Is your 400gal just where it was set?
Can you tell that the water is getting hard before it regens?
You might be able to stretch out that 400gal amount.
The issue is that you can't use a softener to 'partially soften' the water.
It will soften as much as it can until it is exhausted, and then you get hard water.


= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[Compositepro]

Hardness will break through the softener if the water flow rate is too high, as the beads can only exchange ions at a finite rate controlled by diffusion of ions into the beads. It is important to understand this. This flow rate decreases as the beads approach saturation. So the reality can be much more complicated than an equilibrium equation.

 

[bimr]

There are a number of things to look at:

1. You can decrease the salt dosage. You can operate anywhere from 6 lbs salt per cubic feet of resin with a capacity of 20,000 grains to 15 lbs salt per cubic feet with a capacity of 30,000 grains. The leakage of hardness will increase with the lower salt dosage but shouldn't matter with a home unit as you are trying to obtain a zero hardness effluent. Capacity Chart

2. The resin wears out around 10 years of age so you should consider changing the resin.

3. Blend the raw water and softener effluent to obtain 80-120 hardness levels. You don't need zero hardness.

4. There are some brine recycling system that also tend to reduce the efficiency somewhat. Probably not worth the effort to go that way.

5. Consider updating to an RO unit.

 

[FoxRox]

bimr, thank you for that link. That is exactly what I was looking for. Much less salt usage but only slightly harder water.

Now I just need to find a softener that has all those "advanced" settings that I can tweak until I figure out what softens "good enough" but does not negatively affect the septic tank.

Any recommendations?

 

[bimr]

Amazon probably has the most economical selection of water softeners.