Soda Ash Water Treatment vs. Acid Neutralizer: Why We Stopped Installing Soda Ash Systems 20 Years Ago

A caller in New Jersey has a pH of 4.9 and a soda ash injection pump in his basement that came with the house. "What a pain," he said. The man who put it in had told him calcite would not keep up with water that acidic. It will. I told him what I tell everyone who asks me about soda ash: we don't even sell those. His fix is one 2.5 cubic foot tank with calcite and FloMag mixed in, and nothing to mix every month.

What a soda ash injection system is

Soda ash is a white alkaline powder (sodium carbonate). A soda ash injection system pumps a mix of it and water into your water line to raise the pH. The powder dissolves completely in water. It is a real water-treatment chemical, the same one municipal plants use, and yes, it neutralizes acid. The question is what it takes to run it in a house.

The system has more pieces than people expect. There is a solution tank, 15 to 30 gallons, with a small chemical feed pump on its lid. There is a fitting that injects the solution into your water line. And there is a retention tank downstream, usually 80 to 120 gallons, where the solution and the water blend before the water goes to the house. When your well pump kicks on, the little pump kicks on with it.

The job that comes with it is monthly. You mix soda ash powder with warm water and refill the solution tank, and the mix has to be right. Too strong and you have put too much chemical in your drinking water; too weak and it does nothing to the pH. A caller in New York who ran one for years told me his recipe: twelve cups of soda ash to thirty gallons of water, which was the most the water would hold, and that did bring his pH up to 7. It works, as long as you keep getting that mix right.

Soda ash has one real advantage over calcite, which is that it adds no hardness to the water. That gets its own section below, because it is the honest reason some companies still recommend it.

Why I don't sell soda ash systems

I don't sell soda ash systems and I don't recommend them. When we were a service company we never sold one, and we took out hundreds of them over 25 years. People were fed up with the cost of repairing the pump and with having to deal with the thing every month. They would forget about it. We put a neutralizer tank in for them and they were happy.

The part that worries me most is what happens when it stops. If the pump fails or you run out of solution, your water becomes acidic again, and you are back to the copper pipes and the blue-green stains that made you look into this in the first place.

One buyer who ran soda ash for ten years before switching wrote this on our 2.5 cubic foot tank in March 2023: "We were using the acid neutralizer that uses soda ash for 10 years. Over time we couldn't get the pH accurate and the servicing on the product cost us twice as much as the original system. As soon as we installed the Clack system our pH has been perfect." Verified buyer The reviews quoted on this page are verified purchases from our product pages. That is the pattern. It works at first, the pH drifts, the servicing adds up, and eventually the pump comes out and a tank goes in.

How a calcite tank does the same job

A calcite neutralizer is one tank of crushed limestone after your pressure tank. Acidic water dissolves a little of the limestone and comes out neutral. A caller near Dover, Delaware, with a pH of 5.7, put it this way: "It looks like just a tank where the water goes in, and the water comes out." Basically, that is the way they all work. Water in the top, down a center tube, up through the calcite, out to the house. The path is drawn step by step on how an acid neutralizer works.

The part that matters for this comparison is that there is no dose to get right. Calcite is a natural limestone, and it is self-regulating: once the water hits neutral, it stops dissolving the calcite. Nothing to set. One buyer wrote that he appreciated "the simple design with no settings, dials or electronics," and that is the whole idea.

The upkeep is the calcite level. At a pH of 5.7 you will add calcite to a 2.5 cubic foot tank probably every 24 to 36 months. Other than that, there is nothing to do. You check the level by shining a bright light at the tank; once it is about halfway down, it is time to add a bag. The yearly check and the refill, with photos, are on servicing an acid neutralizer.

One thing a Culligan rep told the Delaware caller that I hear a lot: that he needed the backwashing kind. The backwashing has nothing to do with the pH level. It is for wells with high iron or heavy sediment. Ninety-nine percent of the time my customers choose the non-backwashing tank, usually the 2.5, because it has the most capacity and the least pressure drop. The two are compared on backwashing vs non-backwashing.

Soda ash vs calcite side by side

The difference is upkeep. A soda ash system asks something of you every month, and a calcite tank asks for a bag of calcite every few years.

Under three minutes, standing between the two: what each one takes to run, what happens when the pump quits, what to do at pH 4, and what each costs.

What if my pH is 5 or lower?

Very low pH is where soda ash gets recommended. I still would not put one in. Below pH 5.5 I mix FloMag into the calcite, and that has fixed wells down to pH 3.67. FloMag is magnesium oxide, a stronger mineral with five times the pH-raising power of calcite. Plain calcite handles water down to about 5.5 in a 2.5 cubic foot tank; callers at 5.7 and 5.8 got plain calcite. Below 5.5 I add FloMag to each 50-pound bag of calcite, mixed in a storage bin before it goes in the tank, and the lower the pH the more goes in: three pounds a bag for a Maine well at 5.19, four for the caller in the opening at 4.9. The 3.67 well took a custom blend with more FloMag per bag than that.

A caller in Georgia at 5.4 to 5.7, who had talked to two dealers in town about a soda ash system and did not like what he heard, asked me whether a calcite tank would even work at that pH. We treat pH levels down in the threes. In the video I say the same about a pH of 4: both systems will work, and with the tank you just add more FloMag. One thing about size: at low pH the tank has to be bigger, not smaller. A 1.5 cubic foot tank was too small for the caller in the opening, because it would need so much FloMag it would turn into a brick. And the blend makes the water harder than plain calcite does, so plan on a softener; that is the next section.

How common is this? Of the wells my customers have had lab-tested, about one in six comes back below pH 7. One in 25 is below 6. One, out of more than 360, was below 5.5. The very low pH that soda ash gets sold for is rare, and the tank handles it anyway.

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Which one makes the water harder?

The calcite tank does. The limestone that dissolves adds about 3 to 6 grains of hardness. Soda ash adds no hardness; it adds sodium. Hardness is dissolved calcium and magnesium, and soda ash has neither in it. In the video I said soda ash adds a little less hardness. The chemistry is that it adds none, and that is the one honest point in its favor.

Acidic well water usually starts out soft. As I told the Georgia caller, whose water had almost nothing dissolved in it, it is soft because there is no limestone in the ground, and that is why it is acidic. The acidic wells my customers have had lab-tested had a median hardness of about 2.6 grains. A family of six in Pennsylvania at pH 5.8 and 4 grains asked me how much harder it would get: if you are at four, you might go to eight to ten. Some people put the tank in, see where the hardness lands, and skip the softener if it stays low. You can always add a softener later. It just saves a few hundred dollars to buy the two together, and the neutralizer and softener package is what most people at that hardness end up with. Whether you need both is worked through on acid neutralizer and water softener.

The sodium from soda ash is worth knowing about if someone in the house is on a restricted diet. The EPA's drinking water advisory on sodium sets a guidance level of 20 milligrams per liter for people limited to 500 milligrams of sodium a day, and puts the taste threshold at 30 to 60. The same advisory says drinking water is not a significant source of sodium for most people. So for most houses it is not a health issue either way; it is a question of whether you would rather add a softener or mix chemicals.

Can I switch to a calcite tank?

Yes. People call me tired of dealing with the pump and ask whether they can put a calcite tank in instead, and it is not a problem. Two steps, and the first one is the one people skip.

Test the raw water first. The pH that sizes the tank is the pH coming out of the well, before the soda ash goes in, not the number you have been reading at the tap. If your last test was on treated water, take a sample ahead of the injection point, or bypass the pump for a day and test the tap. The certified well water test gives me the pH, the hardness, the iron and the copper from one sample, which is everything I need to tell you plain calcite or the blend, and which size.

Then the plumber takes the pump and the injection fitting out of the line and puts the tank in after the pressure tank, before the water branches off to the water heater and the fixtures. It can go anywhere along that stretch; the Delaware caller wanted his in the garage forty feet from the pump, and people do that all the time. I recommend a licensed plumber for the install, and I support your plumber by phone at 800-460-5810. One buyer who replaced a soda ash unit in 2021 wrote that the installation was "completed by a plumber within 2 hours" and that "in hours water pH is right at 7.1." What ships: the tank, the valve with the bypass on it, the funnel, and the calcite in separate bags to load at install. There is no drain, so no drain line.

Before you size the tank

Test the raw water before you switch

The pH ahead of the soda ash system is the one that sizes the tank. The certified lab test, mailed to you, run by an accredited lab, reports pH, hardness, iron and copper from one sample.

See the certified well water test ($199)

53 contaminants. Results reviewed by Aidan, in plain English. On city water, use the city water test.

Frequently asked questions