# [Wet Thumb Forum]-water softener using potassium



## Lois (Jul 28, 2003)

Hi,
I was searching for info about using a water softener with planted aquariums and found a thread where someone used potassium pellets instead of using salt. I have a Rain Soft water softener and was originally told to use the salt from Home Depot for it. (The Rain Soft people don't seem to know much about anything it seems) I seem to be having trouble with my plants showing deficiencies which I think are related to this system and am also concerned about other problems its causing with my septic system.


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## Roger Miller (Jun 19, 2004)

Water that is softened using ion exchange water softeners is not suitable for growing plants. The calcium and magnesium that are removed by the softener are both essential nutrients. The sodium that the softeners add it not a nutrient and the high sodium/calcium and sodium/magnesium ratio that results in the softened water prevents some plants from using what little calcium and magnesium is available.

You can use potassium chloride in the place of sodium chloride. The Home Depot here sells potassium chloride for water softeners, but it isn't always available. While it is possible to use potassium in your water softener, the results for your plants are not necessarily better for your plants.

If you have a water softener in your home then you need to find a tap in your house that provides unsoftened water. Use either unsoftened water or a mix of softened and unsoftened water.


Roger Miller


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## Lois (Jul 28, 2003)

Roger,
Thanks for the advice. Sorry it took so long to respond (away for the holidays). I have an outside tap that comes directly from our well, surpassing the water treatment system. 
GH=3
KH=0
I've added different chemicals to bring up GH & KH but plants haven't responded as well as hoped. Also even though I'm religious about water changes (1/4-1/3 each week) cyano always seems to be an issue. Could this be from the soft water by any chance? Adding potassium seems to worsen it and plant probs.


Tank parameters are as follows:

N= 5-7 (add Kno3 and Kent's Nitro daily)
Po4= 1 (add Kh2po4 1-2 xs a week)
Fe= 1 (trace element mix daily)
Ca= 2 (add Reef Complete @ water changes)
GH= 6-7 (Reef complete & Mgso4 @ water changes)
KH= 4 (using baking soda @ water changes)

I tried using the equasion for figuring Mgso4, but fish and plants seemed stressed when dosing the amount of Mgso4 to bring 4:1 Ca:Mg ratio. Does this equasion work the same for well water as it does for city water? Mg=(dGhx17.9-Cax2.5)/4.1 

Lois


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## Roger Miller (Jun 19, 2004)

> Originally posted by Lois:
> Also even though I'm religious about water changes (1/4-1/3 each week) cyano always seems to be an issue. Could this be from the soft water by any chance?


Soft water can't be an issue if your specs below are accurate. The water in the tank is not very soft.



> Tank parameters are as follows:
> 
> N= 5-7 (add Kno3 and Kent's Nitro daily)
> Po4= 1 (add Kh2po4 1-2 xs a week)
> ...


The equation works the same regardless of where the water comes from. It *does* require that you use GH in degress and calcium in ppm (or mg/L) and it gives you the result in ppm of magnesium. Given the values in your list above, you now have nearly 25 ppm of magnesium for a Ca:Mg ratio of 1:12.5 or more. That isn't a very good result.

What is the pH?

Roger Miller


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## Lois (Jul 28, 2003)

> The equation works the same regardless of where the water comes from. It *does* require that you use GH in degress and calcium in ppm (or mg/L) and it gives you the result in ppm of magnesium. Given the values in your list above, you now have nearly 25 ppm of magnesium for a Ca:Mg ratio of 1:12.5 or more. That isn't a very good result.
> 
> What is the pH?


pH is ranges from 6.8- around 7.2 depending on my diy co2. I must not properly understand the calculations for Ca:Mg ratio though. Please bear with me I'm not great in math.

If my GH tests at 7 (after adding Ca & Mg in form of Reef Complete) and my Ca tests at 40 (color change after 2 drops from Hagen test kit) then I calculate this way:

(GHx17.9-Cax2.5)/4
(7x17.9-40x2.5)/4
(125.3-100)/4
25.3/4
6.32=Mg
If Ca=40 & Mg=6.32 then 40/6.32=6.329 which gives me 6.32:1 Ca:Mg ratio. What am I figuring that's wrong?

Lois


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## Roger Miller (Jun 19, 2004)

> Originally posted by Lois:
> If Ca=40 & Mg=6.32 then 40/6.32=6.329 which gives me 6.32:1 Ca:Mg ratio. What am I figuring that's wrong?


Nothing in this case. In your earlier letter you listed calcium as 2, which is considerably different from the 40 that you used in this calculation.

Your pH is fine. What is your lighting like? How many and what kind of fish are you keeping? What deficiency symptoms do you see in your plants? How long has the tank been set up?

Roger Miller


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## Lois (Jul 28, 2003)

> Nothing in this case. In your earlier letter you listed calcium as 2, which is considerably different from the 40 that you used in this calculation.


Sorry for the confusion. I meant color in Hagen test changed after 2 drops giving me a reading of 40.



> Your pH is fine. What is your lighting like? How many and what kind of fish are you keeping? What deficiency symptoms do you see in your plants? How long has the tank been set up?


Tank is a 55 gal set up for 1 1/2 years with a low fish load: 2 Discus, 4 Cardinal Tetras, 1 Khuli Loach and 1 Red Minor Tetra. 4-40 watt flourescent tubes on for 11 1/4 hrs. a day. Substrate is a mix of gravel with Flourite below. 
All plants seem to have trouble growing roots which I thought were signs of calcium deficiency. With the added calcium though this doesn't seem to make sense. Worst symptoms show up in 2 of my plants:

*Heatheranthera Zosterfolia* has crinkled, scorched looking leaves with horizontal white streaks running through them. Plants seem to rot especially at base. 
*Rotala Macandras* leaves were originally filled with holes and now have fallen mostly off. New leaves are tiny and pale, mostly green. Plant seems to have trouble growing new roots.
Other plants include _Red Lotus, Limnophilia, Alternanthera Roseafola, Foxtail, Hygrophelia, Rotala Rotundafolia_. 
I'd like to send a picture of the deficiencies but seem to have problems adding the attachment.

Thanks,
Lois


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## Lois (Jul 28, 2003)

Let's see if I can send a picture...
These symptoms seem to worsen when adding potassium in any form.


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## Roger Miller (Jun 19, 2004)

The second photo seems to show fairly healthy H. zosterifolia. I think the crinkling is a normal growth pattern. I'm not sure what might cause the light colored patches. It might be wrong to jump to the conclusion that it is a nutrient problem. If it is a nutrient problem then I lean toward a trace element shortage. The decomposing stems may also not indicate a nutrient problem. It seems pretty normal for H. zosterifolia to put down roots from the stem above the substrate. When that happens the leaves and stems below the roots may break down.

The problem with R. macrandra may also not be a nutrient problem, but if it is one I lean toward a trace element deficiency. R. macrandra in most people's experience is a light-demanding plant, and one that needs a CO2 level high enough to match the light level. 4x40 watt lamps over a 55 gallon tanks may sound like more light than it really is. Your 3 watts/gallon may not be sufficient, depending on the kind of lamp you are using and the design of your hood.

The CO2 level is around 12 ppm, which is fine for most plants that will grow well in moderately lit tanks. You would probably get better results if you used a pressurized system and were able to maintained a more constant supply. If you want to keep fast-growing plants then you probaby also want a higher CO2 level.

I'm not sure what your standard is for good root growth. The photo seems to show nice healthy, white root growth. If there is a problem with root growth then my first inclination is to look for a problem in the substrate rather than in the water.


Roger Miller


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## Lois (Jul 28, 2003)

> The second photo seems to show fairly healthy H. zosterifolia. I think the crinkling is a normal growth pattern. I'm not sure what might cause the light colored patches.


If I hadn't had these plants before I would assume the same, but in the past, Heather was bushy; leaves were long, slender and green with no crinkling nor white streaks. Both Rotala M. & Heather had to be trimmed constantly & both had vast healthy roots below the substrate.

Once I moved and began using well water these problems started. This picture is actually what the plant looked like when it 1st showed deficiency. Since then Heather has more dead areas between stems and Rotala M. has lost most of it's leaves with just a few tiny pale ones left. I've used Flourish as well as a trace element mix with no change.

I also wish I could pinpoint why other plants are struggling with root development or why Cyano keeps creeping in. As I said before, Potassium seems to enhance the problems. Could there be something in my water chemistry that causes K to bring out these problems? I've heard salt can do similar things.

Lois


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## Lois (Jul 28, 2003)

Update. The past coulple of days I've been adding Nitrogen through Kent Botanicals Nitro+. All plants have sent out many new roots. I didn't think my No3 was low; test kit read 5ppm. I was adding it in the form of Kno3 but since my plants seem to respond poorly to the extra K, I began to add it from Kent Botanicals. I don't remember N deficiency being a cause of poor root developement, but could it have hindered the uptake of anoter nutrient?

I'm still waiting to see if Rotala Macandra produces larger leaves & regrows leaves that fell off.

Lois


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