# Water softeners, bad for aquariums?



## PlantedRich (Jul 21, 2010)

It is something of a mixed bag but generally not the best. The softener does use salt to remove the magnesium and calcium from tap water. But the salt doesn't stay in the water there are several cycles. There is a final rinse cycle to rinse the salt out of the softener media. It is not possible to totally rinse all the salt out, much the same as a dishwasher rinsing dishes leaves some detergent. Since salt is often used in medicine for freshwater fish, the salt content left is not a major problem and will not kill fish. Some use salt routinely in freshwater tanks. 
But the downside is that the softwater does not have the calcium and magnesium left which plants and all but the most softwater type fish will need.


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## Diana (Jan 14, 2010)

Good to use RO after a softener. Check with the manufacturer, but I have read that RO membranes do not deal with calcium very well, it tends to clog the media, and age it faster. Plus, the more stuff you can remove by other means, the less there is for the RO to do, so it lasts longer. 

Then add back the right minerals in the right ratios for the livestock you want to keep.


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## GraphicGr8s (Apr 4, 2011)

PlantedRich said:


> It is something of a mixed bag but generally not the best. The softener does use salt to remove the magnesium and calcium from tap water. But the salt doesn't stay in the water there are several cycles. There is a final rinse cycle to rinse the salt out of the softener media. It is not possible to totally rinse all the salt out, much the same as a dishwasher rinsing dishes leaves some detergent. Since salt is often used in medicine for freshwater fish, the salt content left is not a major problem and will not kill fish. Some use salt routinely in freshwater tanks.
> But the downside is that the softwater does not have the calcium and magnesium left which plants and all but the most softwater type fish will need.


The salt does stay in the bed. You are doing an ion exchange with the sodium and the calcium. The salt replenishes the NA.

Also people with a sodium problem shouldn't drink softened water.


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## PlantedRich (Jul 21, 2010)

GraphicGr8s said:


> The salt does stay in the bed. You are doing an ion exchange with the sodium and the calcium. The salt replenishes the NA.
> 
> Also people with a sodium problem shouldn't drink softened water.


Often said but not many have info to back it up. Doctors are often asked and they default to not using softened water but then most doctors know very little about softeners and how they operate. The assumption is that you put all that salt in so it must be in the water. 
Once the operation is fully understood, most would agree that most of the salt is flushed down the drain during the rinse cycle. 
The training I got says that the normal person using softened water receives about the same amount of salt as he gets when he eats a slice of white bread. 
It IS safer to not drink softened water if one is seriously ill but then it is also safer to not eat bread when on the same diet restrictions.
Many people continue to eat potato chips so I no longer give medical advise.


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## s_s (Feb 15, 2012)

It matters very little for someone dosing different salts in excess via EI method. 

It might matter for someone keeping a walstad method planted aquarium, where tap water top-offs are supposed to provide a source of some needed micronutrients.


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## Greggz (May 19, 2008)

I have well water with a softener. I've had no problem with fish or plants (about 8 years running at this home).

You can get some unusual readings. My ph comes out of the tap pretty high (degassed) at 8.25, my kh is very high at 17, and my gh is almost zero. I add GH booster, but other than that, no problems.

I know in theory there could be some issues, but my experience is that in practice there's nothing to worry about. Here is a video of my tank. 

https://www.youtube.com/watch?v=ftK0-DTsqY8


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## GraphicGr8s (Apr 4, 2011)

PlantedRich said:


> Often said but not many have info to back it up. Doctors are often asked and they default to not using softened water but then most doctors know very little about softeners and how they operate. The assumption is that you put all that salt in so it must be in the water.
> Once the operation is fully understood, most would agree that most of the salt is flushed down the drain during the rinse cycle.
> The training I got says that the normal person using softened water receives about the same amount of salt as he gets when he eats a slice of white bread.
> It IS safer to not drink softened water if one is seriously ill but then it is also safer to not eat bread when on the same diet restrictions.
> Many people continue to eat potato chips so I no longer give medical advise.


It's not the salt itself however. We utilize the sodium in salt. Something called a sodium potassium pump we have.

The brine solution recharges the sodium in the beads in the softener. The calcium and magnesium ions are exchanged for the sodium out of the NaCl.

Personally I can't stand the feel of soap with softened water. Never feel clean just slimy.

I practical every day use it may not really matter for fish. But why risk it?


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## Audionut (Apr 24, 2015)

Ion exchange is exactly that, an exchange of ions.

ion-exchange reaction | chemical reaction | Britannica.com


> Ion-exchange reaction, any of a class of chemical reactions *between two substances* (each consisting of positively and negatively charged species called ions) that involves an *exchange of one or more ionic components*.


Exchange | Define Exchange at Dictionary.com


> to give up (something) for something else; part with for some equivalent; change for another.


If the removal of Ca++ and Mg++ ions is not being replaced with the addition of Na+ ions (or other cation), then it is not ion exchange, or the system uses further methods to bind the ions to some substance (De-ionization for instance). The Na+ ions do not get stuck in some bed, or some other place other then the water. The entire point of ion exchange, is to strip free Ca++ and Mg++ cations from the water, and replace those cations with Na+ cations _*in the water*_.
Being able to strip Ca++ and Mg++ without replenishing positive cations defies cation/anion balance.

Na+ cations above trace levels serve no purpose to a planted aquarium.

Medicine isn't my thing, but I like to look at things logically. 
If you have a problem with excess sodium, drinking water that has other useful ions, replaced with sodium ions probably isn't the smartest thing you can do, regardless!!


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## GraphicGr8s (Apr 4, 2011)

Hopefully this simplifies it a bit more.

The heart of a water softener is a mineral tank. It's filled with small polystyrene beads, also known as resin or zeolite. The beads carry a negative charge.

Calcium and magnesium in water both carry positive charges. This means that these minerals will cling to the beads as the hard water passes through the mineral tank. Sodium ions also have positive charges, albeit not as strong as the charge on the calcium and magnesium. When a very strong brine solution is flushed through a tank that has beads already saturated with calcium and magnesium, the sheer volume of the sodium ions is enough to drive the calcium and magnesium ions off the beads. Water softeners have a separate brine tank that uses common salt to create this brine solution
In normal operation, hard water moves into the mineral tank and the calcium and magnesium ions move to the beads, replacing sodium ions. The sodium ions go into the water. Once the beads are saturated with calcium and magnesium, the unit enters a regenerating cycle. First, the backwash phase reverses water flow to flush dirt out of the tank. In the recharge phase, the concentrated sodium-rich salt solution is carried from the brine tank through the mineral tank. The sodium collects on the beads, replacing the calcium and magnesium, which go down the drain. Once this phase is over, the mineral tank is flushed of excess brine and the brine tank is refilled.
How It Works: Water Softener


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## Leeatl (Aug 8, 2015)

We have a softener but our water is soft to begin with so very little salt is exchanged . Just to be on the safe side I turn the valves so the water does not go through the resin and flush the lines a bit when I do water changes . Have been doing for this for a year with no problems .
I like the carbon filter on the system which removes the chlorine and such .


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## PlantedRich (Jul 21, 2010)

For tank use, the salt is not going to be a problem as we often find salt in other things for the tank. For our personal health it is much the same. I'm restricting salt intake at this time because of the massive amount found in our normal foods. doing some figures tells me the amount of salt left in water I drink is so small that it matters very little. A can of soup, a pickle, pasta or a handful of crackers has far more salt so I work on things I can adjust like removing the salt shaker from the table, not eating bacon or sausage and really looking at the foods I do eat. A trip to Burger King can wipe out the recommended use for the whole day. 
If you keep a salt shaker in the kitchen or dining room, the softener is not the problem.


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## jr125 (Mar 5, 2015)

Seems like there should be some kind of salinity test you could use before and after softening to measure the effect. I'm sure safe levels for freshwater aquatic life have been established, although they may vary from fish to fish.


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## Diana (Jan 14, 2010)

API used to make a salt test. It was in the right range for fresh water tanks, too. They sold it for pond use. Have not seen it for years. 
How about this: A TDS meter will react to all the charged materials in the water. Can you figure out what else is in the water, besides salt? Then subtract that from the total. What remains is from sodium chloride. 

OK, a really fast search found this:
Pinpoint Pond Salinity Monitor


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## mistergreen (Dec 9, 2006)

Softeners swap out Ca for Na. Figure out the Ca from your water municipal report. That should roughly be the amount of Na, I figure.


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## Zhylis (Nov 25, 2015)

There is minimal effect on water salinity; the water from a softener doesn't taste "salty". The only thing being added into the water is sodium ions. Not salt.

And the amount of sodium introduced into the "softened" water will be double the original amount of calcium. Ion exchange resins need to balance the charge. Since calcium ions are 2+, two Na+ are released for every single calcium that is bound. That's why water softeners can potentially be an issue_ if you have very hard water_. You'll spike your TDS above anything biologically relevant for freshwater. It only becomes an issue if 1. An organism is dependent on a sodium channel for some function, 2. The TDS of the water shifts the osmotic balance so that water exits the plant/animal (dehydration), or 3. The TDS of the water is high enough to interfere with oxygen transport in the fish gill. (EDIT: Usually only an problem if you continuously top off a tank with softened water without doing regular large water changes.)


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## PlantedRich (Jul 21, 2010)

So I come back around to what I first said. Without exact numbers, I can say it isn't a big problem as it will not "poison" the tank as it will never reach the salt level that many who add salt would use. Nothing anywhere near when we use salt to treat ich. But over time, I think the loss of calcium and magnesium would be the first thing to effect fish, plants, or snails. If one were forced to use softened water, it could be covered by adding back the minerals removed but then that is a bit more complex that using raw water. 

For our personal health the question becomes how strict you want to be on removing salt from your diet. There is certainly way too much in what most of us eat but there are so many easier ways to cut back on salt that avoiding softened water really is not worth the effort. Most of us don't recognize how much salt is used in what we eat so we need to do some label reading. If the salt shaker is on the table you are likely to be eating too much salt! Check what a hamburger bun gives you and you can see the water is not the problem. And it's not safe to even walk by a jar of olives or a cup of chicken broth!


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## GraphicGr8s (Apr 4, 2011)

You all keep talking about softeners adding salt to tap water and they do no such thing. They take out the calcium and add sodium. The NaCl bond is broken. 
Pools can use a salt chlorine generator for chlorine. Even though you are using salt that doesn't make a pool salty. Just like a softener doesn't add any salt to tap water.


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## Diverdoc (Jan 10, 2016)

*An in softened water*

One for people the amount of na in softened water is minuscule and so small an addition it doesn't matter at all. For fish the loss of ca and mg maybe an issue but almost never is unless you have some rare African species and no plants. For plants no magnesium can be an issue but usually not enough of one to matter. And na cl in the water is the same as the ca and mg in the water and the explanation for how it works was excellent. And I am a doctor.


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