Use water from water softener

At home we have a water softener which makes the water really soft.
I haven't setup my tank so I'm asking before I do anything, just to be sure.

The test with the soft water gave me a GH reading of <3
KH is 6 which surprises me as I thought the softener would remove most of the stuff so the KH would drop.
Ph is between 7 and 7.5. The test I have give me a reading between 3 and 10. I will get a more accurate one...

I checked the pipes and there's no way for me to get water before it gets processed...

So.. can I use that water to fill my tank? Do I just need to treat it with a water conditioner? Or what is the best thing to do?

Worst case is to get the water from my mother's house. She lives 10min drive from here. It's not ideal, especially since it's a 240 liter tank...

 

In general it is my understanding that water softener water should not be used. However, whether you can get away with it or not depends on the kind of fish and plants you keep.

I have a water softener also. I by-pass the water softener for my tank water. My water softener has valves I can open and close to by-pass the softener. After I by-pass the softener, I run the water for a while to get the soft water out of the pipes before I draw water for the tanks.

I was oblivious to this issue when I set my tank up. My guppies seemed to do fine in the soft water, but not my plants. My plants are doing much better with the non-softened water. I think the issue for my plants was a combination of mineral deficiency and sodium.

I have considered using potassium chloride rather than sodium chloride for the water softer. I think that might work if I also replenish the minerals. I do not think replenishing the minerals is sufficient if there is sodium since I think the sodium hurts the plants.

Following are two thread in which I asked questions related to my water softener:

Water Softener | Aquarium Water 431582

Strange GH reading? | Aquarium Water 429749

 

I wouldn’t

 

Water softener only remove gH, it does not touch kH.

It replaces Ca and Mg with Na or K.

So it doesn't really soften the water in terms of carbonate hardness.

 

I agree it’s not the best idea.
What’s the plan for the tank though?

 

Usually outside faucets are not connected to any water softener. Might want to check on that.

 

Thanks for the info.

so if a softener doesn’t touch the kh. Why is it bad? Is the added Na or sodium bad for the fish?Or do the fish require the things removed by the softener like Ca and Mg?

Can I treat the water somehow so it can be used or is there no fix?

we don’t have an outside connection that I can use... so if I really can’t use the soft water, I have to get it at the neighbours or family...

I’m planning a planted tropical tank with angelfish and some small gourami and corydoras and a small pleco.

 

Thanks for the info.

so if a softener doesn’t touch the kh. Why is it bad? Is the added Na or sodium bad for the fish?Or do the fish require the things removed by the softener like Ca and Mg?

Can I treat the water somehow so it can be used or is there no fix?

we don’t have an outside connection that I can use... so if I really can’t use the soft water, I have to get it at the neighbours or family...

I’m planning a planted tropical tank with angelfish and some small gourami and corydoras and a small pleco.

For what you’re plans are I definitely wouldn’t use it.
Your reasons above that you asked about are why.

 

You can use it but you’ll have to add Ca and Mg back.

CaSO4 for calcium
MgSO4 for magnesium

The water won’t be ideal for plants or fish, but it can work. Definitely pick up a kH and gH test kit, and consider a pH pen that comes with calibration fluid off amazon and a tds meter.

 

I used softened water for several years, bred fish in it, kept just about everything in it, never had any problems that pointed to the water softener. The general claim is that it adds too much sodium, but a chemist I know says the amount is negligible, even in very hard water. BTW, I also grew plants in it with no difficulty.

I have never seen any empirical evidence that softened water is bad for the fish, only the claims of concern. This appears to be one of those ideas that gets repeated so often that it is assumed to be true without evidence.

 

Water softener only remove gH, it does not touch kH.

It replaces Ca and Mg with Na or K.

So it doesn't really soften the water in terms of carbonate hardness.

That there is the answer. If you want to "re-harden" your water, use RO right or discus buffer. Works great.

 

I used softened water for several years, bred fish in it, kept just about everything in it, never had any problems that pointed to the water softener. The general claim is that it adds too much sodium, but a chemist I know says the amount is negligible, even in very hard water. BTW, I also grew plants in it with no difficulty.

I have never seen any empirical evidence that softened water is bad for the fish, only the claims of concern. This appears to be one of those ideas that gets repeated so often that it is assumed to be true without evidence.

thanks for this... how did you treat the water? Did you treat is a regular water so you added a conditioner you use for normal water or what did you do?
As soft water has no or almost no Mg or Ca, what did you do to counter that?

 

thanks for this... how did you treat the water? Did you treat is a regular water so you added a conditioner you use for normal water or what did you do?
As soft water has no or almost no Mg or Ca, what did you do to counter that?

It's not actually softened... It's stripped of Ca and Mg. It contains all of it's carbonate hardness, giving the water it's "hard" designation.

You can use it no problem but:

You can use it but you’ll have to add Ca and Mg back.

CaSO4 for calcium
MgSO4 for magnesium

The water won’t be ideal for plants or fish, but it can work. Definitely pick up a kH and gH test kit, and consider a pH pen that comes with calibration fluid off amazon and a tds meter.

 

I have a well, with extremely hard water, which is why we wanted the water softener in the first place. There was no need to treat the softened well water.

 

So from what I can tell and see online there are few people who are actually succeeding with softened water, however the effects of this might be rather long term so nobody is sure if the few deaths they have is because of the water or something else so it's rather iffy...

I also notice that the people with success in softened water, are the ones who are using water from a well. I'm not on a well so not sure how big of a difference that makes.

I've been doing some further reading and the general consensus is that the sodium that is added to the soft water, in combination with the lack of Mg and Ca will cause long term disaster for the fish as sodium doesn't have the same electrolytic properties as Mg and Ca which is used by a lot of fish.

I don't think I'll take the risk and will find another solution. There is just to much info around the ill effect of softened water and yes, there are people who succeed with it but it's probably the same with the guppy and betta discussion... It's advised against it but people do have success with it...

 

I see a lot of people saying not to use it because it's "bad", but none who have actually used a water softener saying that it caused problems. I can imagine that it might be troublesome for Tanganyikan Cichlids, but I have not seen anyone who actually tried it.

 

I did not have any problems with water softener water my fish (guppies and Betta). I did have problems with plants.

 

My water is softened and it's not an issue with my guppies or plants (though that might be why I'm having trouble with my dwarf water lettuce, maybe???). My anubias, flame moss, java ferns, hornwort, cabomba, and ludwigia don't seem to be having any difficulty. I've thrown a couple shells into the substrate (mostly oyster, but a couple others as well) and it's fine. I don't measure things like KH or GH, but my tank is thriving. Some species are doing better than others (see DWL comment earlier, and my shrimp population is struggling) but overall I certainly wouldn't say you "can't" or "shouldn't" use softened water if its the easiest water to use. I certainly wouldn't say my tank is struggling for survival!

 

I second chromedome52. I worried about this as well since I also have a water softener. Some chemist somewhere (I think it was here on FL) posted some chart which illustrated the negligible salt concentrations in your softened water based on how hard your initial water was. It was surprisingly low, and really put me at ease. That being said, there are some fish species and shrimp that don't tolerate salt well, so do your research. I've kept my neon tetras and dwarf gourami in tip top shape without any health maladies in nothing but softened water for over a year now.

 

Thanks. So why does everybody advises so strongly against it if there seem to be many people with positive experience?
I checked with the water company and the average hardeness in our area is around 17 so that’s rather hard... does that mean our softened water will have more salts then when it initially would be less hard?

 

Thanks. So why does everybody advises so strongly against it if there seem to be many people with positive experience?
I checked with the water company and the average hardeness in our area is around 17 so that’s rather hard... does that mean our softened water will have more salts then when it initially would be less hard?

17 what?

 

17 what?

oh right... Keep forgetting about the different units used for this...
17 dH
303 ppm according to an online convertor.

 

oh right... Keep forgetting about the different units used for this...
17 dH
303 ppm according to an online convertor.

17 degrees of what?

 

17 degrees of what?

17 german degrees

Water hardness is often not expressed as a molar concentration, but rather in various units, such as degrees of general hardness (dGH), German degrees (°dH), parts per million (ppm, mg/L, or American degrees), grains per gallon (gpg), English degrees (°e, e, or °Clark), or French degrees (°fH, °f or °HF; lowercase f is used to prevent confusion with degrees Fahrenheit). The table below shows conversion factors between the various units.

source: Hard water - Wikipedia

 

17 german degrees



source: Hard water - Wikipedia

17 German degrees of what? degrees of kH or degrees of gH? Most water reports I've looked at don't specify, they simply indicate "hardness" which is why I recommend a kH / gH test kit, $10 very well spent. Now we can test for the difference and make adjustments as needed.

kH or gH - they are two different things.

Water softener will strip all of the gH, and leave all of the kH.

kH is what makes water "soft" or "hard" for our use and purposes, not what we think as hard vs soft water (calcium deposits on faucets / showers etc.).

Having a high gH in our minds = hard water, we don't ever think of carbonates (kH) as being hard vs soft.

In aquariums, kH is the true hardness, as it affects osmotic pressures in livestock, plants, and works with pH in buffering.

gH is simply the sum of Ca and Mg within the water. Plants, fish and shrimp need Ca and Mg.

Using a softener for aquariums is fine, so long as you replace some gH with CaSO4 and MgSO4.

This will raise TDS to fairly high levels.

My tap water has a kH of 15 degrees, and a gH of 17 degrees. My water out of the softener has 0 degrees of gH and 15 degrees of kH. I add CaSO4 and MgSO4 to achieve 25-30 ppm Ca and 10ppm Mg, resulting in a TDS of ~475ppm. This results in a degassed pH of 8.2.

This isn't ideal, but it can work.

 

Thanks. So why does everybody advises so strongly against it if there seem to be many people with positive experience?
I checked with the water company and the average hardeness in our area is around 17 so that’s rather hard... does that mean our softened water will have more salts then when it initially would be less hard?

I think it depends upon what fish you are going to keep. From what I gather, fish that prefer soft, acidic water with low TDS will not do well with water softener water. One reason is that, as stated above, you are replacing magnesium and calcium with salt, and the TDS stays relatively high.

 

17 German degrees of what? degrees of kH or degrees of gH? Most water reports I've looked at don't specify, they simply indicate "hardness" which is why I recommend a kH / gH test kit, $10 very well spent. Now we can test for the difference and make adjustments as needed.

kH or gH - they are two different things.

Water softener will strip all of the gH, and leave all of the kH.

kH is what makes water "soft" or "hard" for our use and purposes, not what we think as hard vs soft water (calcium deposits on faucets / showers etc.).

Having a high gH in our minds = hard water, we don't ever think of carbonates (kH) as being hard vs soft.

In aquariums, kH is the true hardness, as it affects osmotic pressures in livestock, plants, and works with pH in buffering.

gH is simply the sum of Ca and Mg within the water. Plants, fish and shrimp need Ca and Mg.

Using a softener for aquariums is fine, so long as you replace some gH with CaSO4 and MgSO4.

This will raise TDS to fairly high levels.

My tap water has a kH of 15 degrees, and a gH of 17 degrees. My water out of the softener has 0 degrees of gH and 15 degrees of kH. I add CaSO4 and MgSO4 to achieve 25-30 ppm Ca and 10ppm Mg, resulting in a TDS of ~475ppm. This results in a degassed pH of 8.2.

This isn't ideal, but it can work.

Right, yes. Sorry my bad...
I was talking about 17 degrees gH while the kH is around 16.
I tested the water after the softener and the gH is around 0 but kH remains around 16.

Meanwhile I already called a handyman to install a faucet before the softener so I can use that.

And the CaSO4 and MgSO4, is that something the local fish store will supply or do I need to get it somewhere else?
I'm hesitant in going that route as it adds additional things that can go wrong...

Also, if the kH remains the same after the softener, will adding CaSO4 and MgSO4 not raise the kH even more? Doesn't that have an ill effect on the fish?

 

Right, yes. Sorry my bad...
I was talking about 17 degrees gH while the kH is around 16.
I tested the water after the softener and the gH is around 0 but kH remains around 16.

Meanwhile I already called a handyman to install a faucet before the softener so I can use that.

And the CaSO4 and MgSO4, is that something the local fish store will supply or do I need to get it somewhere else?
I'm hesitant in going that route as it adds additional things that can go wrong...

Also, if the kH remains the same after the softener, will adding CaSO4 and MgSO4 not raise the kH even more? Doesn't that have an ill effect on the fish?

No, gH is made up of Ca and Mg. Adding CaSO4 and MgSO4 = raising gH = 0 affect on kH.

CaSO4 adds Ca and SO4
MgSO4 adds Mg and SO4

to raise kH you must add carbonates (CO3 2-)

Simply add the same amount of each compound to the same amount of water changed and your levels will stay the same.

For example:

Pep 5 gallon pail:

1.93 grams of CaSO4 (equivalent to 1/2 tsp + 1/16 tsp + 1/32 tsp + 1/64 tsp) = 30 ppm Ca / 4 degrees of gH

1.92 grams of MgSO4 (equivalent to 1/4 tsp + 1/8 tsp) = 10ppm Mg / 2 degrees gH

Total = 30ppm Ca, 10ppm Mg and 6-7 degrees of gH.

Add this into your incoming water change water, do not add this into top off water.

If you are plumbing in a bypass, you don't have to do this.

 

ah ok, now I get it...
gH only measures Ca and Mg while Kh is Carbonates.

And the added minerals by the softener (sodium) has no effect on the fish or plants?

 

ah ok, now I get it...
gH only measures Ca and Mg while Kh is Carbonates.

And the added minerals by the softener (sodium) has no effect on the fish or plants?

It probably does a little bit, but for most tanks it's not an issue. Getting into higher tech planted tanks, breeding or keeping finicky fish species or shrimps etc. is where issues can pop up. At that point it makes sense to bypass the softener or install a reverse osmosis unit and create any water parameter you want.