Neutralizer after water softener and anion tank (nitrates)?

[Nubomb]

Is this the correct setup? It’s a three system setup. Well water that is very hard and low PH. My understanding is the neutralizer will raise the hardness after it was already softened which seems to defeat the purpose or I need to over soften to compensate? I also understand the anion reaction may decrease the PH, which then makes sense for it to be before the neutralizer?

The softener and anion are set to backwash at 1500 gallons of use (Clack). The neutralizer has an old controller with the tabs and is set for twice a week. Neutralizer backwashing lots of water appears to be causing more regen cycles which is another reason I think the neutralizer should be first?

Thoughts and what should I ask the installer?

 

[Nubomb]

No love?

 

[Sponsor]

 

[Bannerman]

or I need to over soften to compensate? I also understand the anion reaction may decrease the PH, which then makes sense for it to be before the neutralizer?

Anion resin should be exposed to as little hardness as possible.

Usual treatment order: Acid Neutralizer > Softener > Anion filter.

There is no 'over softening to compensate' as softeners are designed to remove hardness. Depending on the salt & capacity setting, the amount of typical hardness leakage through the resin will be in the 6-10 ppm range which is less than 1 grain per gallon. 1 GPG = 17.1 ppm.

 

[All Things Handy]

Anion resin should be exposed to as little hardness as possible.

Usual treatment order: Acid Neutralizer > Softener > Anion filter.

There is no 'over softening to compensate' as softeners are designed to remove hardness. Depending on the salt & capacity setting, the amount of typical hardness leakage through the resin will be in the 6-10 ppm range which is less than 1 grain per gallon. 1 GPG = 17.1 ppm.

How much does the Anion treatment lower the pH?

 

[Gsmith22]

Well water that is very hard and low PH.

"very hard" and "low PH" need numbers to really help. But I'll take a shot:

soften first (for hardness), anion second (for nitrates), and then raise pH with soda ash injection so you don't screw up the hardness again. ditch the neutralizer which might fix the pH but will certialy re-raise the hardness. generally neutralizers work with small pH changes but your anion resin might be asking too much of a neutralizer. there is a way to supplement the neutralizer's Calcite with Corosex for greater pH change.

you don't say what type of cation and anion resisn are being used - I'm going to assume Na+ flavor for cation and Cl- flavor for anion and that this is not a demineralization setup (which would use H+ and OH-, respectively). how low the pH goes with the anion resin will depend on the water constituents so it really isn't possible to say - you test pH and adjust the soda ash injection to balance out the pH drop. That being said, pH drop from say ~7 pre-anion to 4 post-anion is certainly possible although a smaller drop is more likely. Just as a water softener (cation resin) will remove all the other positively charged ions besides Ca++ (Mg, Fe, Mg, etc.), so too will your anion resin remove all the other negatively changed ions besides nitrate - sulfates and bicarbonates being the most common. Removal of the bicarbonates will be what causes the pH change - bicarbonate is the backbone of alkalinity and buffering pH changes. you can probably find an online graph of CO2 and bicarbonate equilibrium in water over the pH scale. All bicarbonate will be gone from the water around pH 4. That is why I mentioned the ~7ish to 4 pH change because if your anion resin takes out all the bicarbonate, it will settle around pH of 4.

 

[All Things Handy]

"very hard" and "low PH" need numbers to really help. But I'll take a shot:

soften first (for hardness), anion second (for nitrates), and then raise pH with soda ash injection so you don't screw up the hardness again. ditch the neutralizer which might fix the pH but will certialy re-raise the hardness. generally neutralizers work with small pH changes but your anion resin might be asking too much of a neutralizer. there is a way to supplement the neutralizer's Calcite with Corosex for greater pH change.

you don't say what type of cation and anion resisn are being used - I'm going to assume Na+ flavor for cation and Cl- flavor for anion and that this is not a demineralization setup (which would use H+ and OH-, respectively). how low the pH goes with the anion resin will depend on the water constituents so it really isn't possible to say - you test pH and adjust the soda ash injection to balance out the pH drop. That being said, pH drop from say ~7 pre-anion to 4 post-anion is certainly possible although a smaller drop is more likely. Just as a water softener (cation resin) will remove all the other positively charged ions besides Ca++ (Mg, Fe, Mg, etc.), so too will your anion resin remove all the other negatively changed ions besides nitrate - sulfates and bicarbonates being the most common. Removal of the bicarbonates will be what causes the pH change - bicarbonate is the backbone of alkalinity and buffering pH changes. you can probably find an online graph of CO2 and bicarbonate equilibrium in water over the pH scale. All bicarbonate will be gone from the water around pH 4. That is why I mentioned the ~7ish to 4 pH change because if your anion resin takes out all the bicarbonate, it will settle around pH of 4.

Great Info- thank you....here are more details...please let me know your thoughts:

- Raw untreated Incoming pH=6.35
- Hardness 8.6 grains
- Anion Resin= SBG2 (chloride form type 2 gel strong base anion resin)

The current calcite acid neutralizer brings the pH from 6.35 to 8. And increases the Hardness 2.5 grains afterwards.

What are your thoughts on how much the Anion will lower the pH if its placed at the end of the line?

Thoughts on: Acid Neutralizer > Softener > Anion filter.... Do you think the pH of 8 is high enough to compensate the pH drop by the Anion resin? Will it strip all of the alkalinity?

Thanks


Thanks

 

[Gsmith22]

we are guessing because we don't have actual numbers of all the dissolved solids in the water. even if we did have numbers, the anion resin tends to be tricky - kind of have to try and see what happens. one thing to keep in mind, is that both cation and anion resins remove what you are intersted in and then all of the other similar ions that you may or may not be interested in removing. most of the positively changed ions that get removed by the softener with Ca++ are good to have removed (Mg creates hardness too, Fe and Mn stain, etc.). Same with the negatively charged ions - drinking nitrates, sulfates aren't good either but the one thing that anion removes that is beneficial is bicarbonate. its beneficial because it controls changes in pH which can affect your plumbing. one thing also to remember is that corrosion isn't just pH, its a combination of things. LSI is a better measure of if the water is corrosive than pH alone. some thoughts:

if you keep the order softener -> anion - > neutralizer, I would just point out that 2.5 grains is not particularly hard so some would probably deem that acceptable. however, you would likely have hardness buildup on stuff over time, may have to replace water heater more frequently than most, etc. with the neutralizer after the anion, you have acceptable pH and bicarbonates would be added back so LSI would likely be positive, but not sure how positive and too positive is bad too. best way to check would be to use the LSI index of that water to see where it falls for deposition of calcium.

if you change the order to neutralizer -> softener - > anion. i think you will probably be below 7 after the anion. But even if you still remained with a pH above 7, you will have removed most if not all of the bicarbonates from the water by the anion leaving you with a water that can very easily change pH (bicarbonates are the alkalinity/buffer). so even with a pH above 7, I would bet that the LSI would be very negative and you would still get corrosion. if you go this route, I would definatley look into soda ash injection after the anion which would both raise the pH and get you your bicarbonates back all without adding additional hardness (Ca++).

 

[All Things Handy]

we are guessing because we don't have actual numbers of all the dissolved solids in the water. even if we did have numbers, the anion resin tends to be tricky - kind of have to try and see what happens. one thing to keep in mind, is that both cation and anion resins remove what you are intersted in and then all of the other similar ions that you may or may not be interested in removing. most of the positively changed ions that get removed by the softener with Ca++ are good to have removed (Mg creates hardness too, Fe and Mn stain, etc.). Same with the negatively charged ions - drinking nitrates, sulfates aren't good either but the one thing that anion removes that is beneficial is bicarbonate. its beneficial because it controls changes in pH which can affect your plumbing. one thing also to remember is that corrosion isn't just pH, its a combination of things. LSI is a better measure of if the water is corrosive than pH alone. some thoughts:

if you keep the order softener -> anion - > neutralizer, I would just point out that 2.5 grains is not particularly hard so some would probably deem that acceptable. however, you would likely have hardness buildup on stuff over time, may have to replace water heater more frequently than most, etc. with the neutralizer after the anion, you have acceptable pH and bicarbonates would be added back so LSI would likely be positive, but not sure how positive and too positive is bad too. best way to check would be to use the LSI index of that water to see where it falls for deposition of calcium.

if you change the order to neutralizer -> softener - > anion. i think you will probably be below 7 after the anion. But even if you still remained with a pH above 7, you will have removed most if not all of the bicarbonates from the water by the anion leaving you with a water that can very easily change pH (bicarbonates are the alkalinity/buffer). so even with a pH above 7, I would bet that the LSI would be very negative and you would still get corrosion. if you go this route, I would definatley look into soda ash injection after the anion which would both raise the pH and get you your bicarbonates back all without adding additional hardness (Ca++).

Thanks for your in-depth reply...great information, thank you.

I spoke to the water treatment company they had suggested:
Anion > Acid Neutralizer (since the anion lowers the pH) > Water softener.

But the water treatment company is a little concerned that in this order the maganese (0.30 mg/L) from the raw water might coat the Anion resin (they did say i could keep an eye on it and see if the resin turns black to treat the brine tank with Iron-Out)- as a possibility. I am not sure I want to take a risk damaging the resin due to the fact that it is being backwashed with Hard untreated water...

What are your thoughts on this approach?

Thanks!!

 

[Gsmith22]

anion resin is required to be fed with softened water. so the softener has to be before the anion. if a water treatment company suggested that, i would be very careful with their advice

 

[All Things Handy]

anion resin is required to be fed with softened water. so the softener has to be before the anion. if a water treatment company suggested that, i would be very careful with their advice

thank you, i agree. Thats why i wanted to reach out on this forum, appreciate all of your advice!