# [Wet Thumb Forum]-LOW GH, high KH



## javalee (May 8, 2006)

Hi, I've skipped over from the "El Naturel" forum because my tap water is decidedly un-natural. Diana Walstad recommends a minimum GH of 8 for a natural aquarium. Problem is my GH is 1d, while my KH is 20d. So how can I raise the Ca and Mg without adding carbonate?

Good suggestions I've gotten on the other forum are adding Equilibrium (BUT I have high iron and manganese already), or adding CaCl2 and MgSO4. We're wondering which is worse, adding extra chloride ions or adding sulfate? I wondered about adding Ca(NO3)2 instead of CaCl2.

Thanks


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## Roger Miller (Jun 19, 2004)

First I have to ask why your water has low GH and high KH. Water supplies that come that way naturally are unusual -- they are supplied by ground water from wells in sand or sandstone aquifers. More often that kind of water is the result of artificial softening. Do you have a water softener?

Adding calcium chloride and magnesium sulfate is the best way to increase GH without increasing KH. Chloride is biologically benign, it will have no effect on plants or fish unless you add so much that the water gets brackish. Sulfate is also biologically benign under most conditions that support life. Under anaerobic conditions it becomes bacteria food, but sulfate won't create those conditions itself.

In all probability your tap water already contains significant amounts of both chloride and sulfate. 

How much are you thinking of adding? If you add enough calcium nitrate to get the GH very high then your resulting nitrate concentration will be high.


Roger Miller


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## javalee (May 8, 2006)

Thanks for the reply Roger. We do have water from a deep aquifer---the same aquifer that Kentwood and Abita bottled water use.

I'm fine with using CaCl2 instead of Ca(NO3)2 if you think it's a better idea







because of the nitrates. I have NO experience with this stuff. I have trouble getting my nitrate up to 5ppm in this tank so I thought it may work. I hadn't done any calculations yet.


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## Roger Miller (Jun 19, 2004)

javalee,

In this message:

http://aquabotanicwetthumb.infopop.cc/groupee/forums/a/.../876106225#876106225

I described how to dose CaCl2 from sidewalk deicer.

There are several sources for figuring out how to dose epson salt for magnesium.

By most recommendations, you want to get more GH from the calcium than from the magnesium.

Roger Miller


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## javalee (May 8, 2006)

Thank you Roger!


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## javalee (May 8, 2006)

Roger, would you mind returning to the subject of Calcium Nitrate? I ask only because it was so cheap and easy to obtain at our local farmers' co-op. I can always order some CaCl2 online if this doesn't work. 

15.5% Nitrogen as 14.5% nitrate & 1.0% ammonium
19% Calcium
1% Chloride

What do you think? That ammonium of 1% sounds a little scary to me. The bag says add one teaspoon per plant or tree! This tank has 0 Nitrogen right now. But I'm very attached to the fish and shrimp in there, and don't want to poison them. Sound a little risky?


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## Roger Miller (Jun 19, 2004)

javalee,

Calcium nitrate is a far better source of nitrate then it is of calcium. If you were using pure calcium nitrate -- and the product you cited the analysis for is not even close -- then the nitrate concentration that you add from calcium nitrate will be about 3 times the calcium concentration -- more precisely, 3.1 times.

For example, say you wanted to use calcium nitrate to increase GH by 3 degrees. That means adding about 21 ppm of calcium. The resulting nitrate concentration would be about 65 ppm.

Nitrate isn't very toxic, but I understand that high nitrate levels can be associated with some health problems in fish. I don't know what effect it might have on invertebrates.

The ammonium is probably not much of a problem.


Roger Miller


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## javalee (May 8, 2006)

Thanks again Roger! I'll let y'all know how this all works out. I got the epsom salt too.


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## javalee (May 8, 2006)

Well, I don't think this fertilizer (calcium nitrate) is gonna work because of the ammonium in it. 

I added one pellet to two cups of water and it raised the GH from 0d to 4d, but it also raised the ammonia to 3 or 4 ppm!!

I didn't even bother to test the nitrate levels after that. That's just a bad proportion of ammonium to calcium to work with. I'll have to go back to the CaCl2, as you suggested Roger.


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## javalee (May 8, 2006)

Here's another interesting possible supplement, although I already ordered my CaCl2. Burton's Water Salts for beer brewing is a mixture of Calcium sulfate, potassium chloride, and magnesium sulfate. it is made to mimic the water hardness of the river water in Burton England. It's really cheap and can be ordered in small quantities.


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## Roger Miller (Jun 19, 2004)

Burton's Water Salts sounds like an interesting option. Do they give you any information on the relative proportions of the different components? 

Calcium sulfate is soluble, but only rather slowly soluble. If you use a mix with calcium sulfate it is probably a good idea to mix it up outside the tank before you add it, just to make sure that it all gets dissolved.


Roger Miller


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## Dave P (Dec 13, 2005)

> Calcium nitrate is a far better source of nitrate then it is of calcium. If you were using pure calcium nitrate -- and the product you cited the analysis for is not even close -- then the nitrate concentration that you add from calcium nitrate will be about 3 times the calcium concentration -- more precisely, 3.1 times.


Roger, isn't the formula for calcium nitrate Ca(NO3)2? For every mole of Ca(NO3)2 that ionizes in solution, you should get 2 moles of nitrate, right? I'm trying to figure out where you arrived at 3.1

I too, would like to raise my GH without impacting KH, which is why I'm following this thread. It's been some time since I was last in a chemistry class, so please accept my apologies if I'm overlooking the obvious.

Thanks in advance,
Dave


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## Roger Miller (Jun 19, 2004)

Dave,

A mole of calcium is 40 grams. A mole of nitrate is 62 grams. Calcium nitrate contains 40 grams ( 1 mole) of calcium and 124 grams (2 moles) of nitrate. The ratio is 124/40 or 3.1.


Roger Miller


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## Dave P (Dec 13, 2005)

> Originally posted by Roger Miller:
> Dave,
> 
> A mole of calcium is 40 grams. A mole of nitrate is 62 grams. Calcium nitrate contains 40 grams ( 1 mole) of calcium and 124 grams (2 moles) of nitrate. The ratio is 124/40 or 3.1.
> ...


Roger, I think you've calculated a molar mass ratio, not a concentration ratio. Concentration is typically expressed as mol/L. Even though nitrate has a greater molecular weight than calcium, that doesn't necessarily mean that it is in greater concentration in solution. If I'm correct, 1 mole of Ca(NO3)2 should ionize in solution to produce 1 mole of Ca++ and 2 moles of (NO3)-. That would mean that the concentration of nitrate in solution is twice that of calcium.

That's the way I remember it; although, I'll readily admit that I could be wrong.


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## Roger Miller (Jun 19, 2004)

Dave,

Concentrations are almost always cited in weight per volume of weight per weight. The common units are either milligrams/L or parts per million. In fresh water those units are equivalent.

In particular, there are no test kits available in the hobby market that produce measurements in molar units. Even in professional applications, concentrations are almost always reported in weight units. 

In the specific case of nitrate there is some variation in that some results are cited as mg/L of nitrate and others are cited as mg/L of the nitrogen contained in the nitrate. It's still a weight measure either way.


Roger Miller


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## Dave P (Dec 13, 2005)

> Concentrations are almost always cited in weight per volume of weight per weight. The common units are either milligrams/L or parts per million. In fresh water those units are equivalent.
> 
> In particular, there are no test kits available in the hobby market that produce measurements in molar units. Even in professional applications, concentrations are almost always reported in weight units.


This is true; however it would be easy to convert between the two. These kits could just as easily express their measurements in molar units.

Concentration, as I understand it, is the number of "particles" per unit volume solution -- in this discussion, ions are the "particles". It is not reliant on how much they weigh.

For example: Suppose I have 1 _molecule_ of cesium chloride, CsCl (mw 168.3584 g/mol). If I add this CsCl to aqueous solution, it will ionize to yield 1 ion of Cs+ and 1 ion of Cl-. Now, Cs+ is about 3.75 times heavier than Cl-; however, the molar ratio is still 1, meaning that they both exist in solution at equal concentrations. There is only one ion of Cs+ and only one ion of Cl- in solution. You cannot compare the concentrations of ionic species by mass (weight).


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## Roger Miller (Jun 19, 2004)

Dave,

Concentration can be cited with a number of different units. By common usage in studies of aqueous concentrations in natural media the concentrations are cited as weight concentrations. Other fields of analysis may use different common units, but in the specific case of water quality concerns there are very few exceptions. If you were to cite values in molar concentrations you would just confuse and/or annoy everyone.

Ionic balances and thermochemical calculations need values in molar equivalents, molarity or molality. Aqueous concentrations are reported in weight units, converted to molar units for the calculations and the results are usually reported in weight concentrations. The pH/KH/CO2 relationships are an example of that. The conversions are inherent in the constants in the formula.

Both hardness and alkalinity are measured in molar units (molar equivalents, to be specific) but they are rarely reported in those units. The analytical results are converted to the equivalent mass of calcium oxide or calcium carbonate and reported in weight units (ppm CaCO3 or degrees).

The only chemical aqueous concentration I can think of that is usually reported in molar units is hydrogen, which is often reported in nanomoles/Liter. The atomic weight of hydrogen is essentially 1, so in this case the difference between a weight concentration and a molar concentration is just a difference in terminology.

For background, I'm a professional hydrogeologist with a specialization in geochemistry. I've been dealing with water analyses and water quality issues of all types for about 25 years. I've also been keeping aquariums for most of the last 40 years.


Roger Miller


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## Dave P (Dec 13, 2005)

> Concentration can be cited with a number of different units. By common usage in studies of aqueous concentrations in natural media the concentrations are cited as weight concentrations. Other fields of analysis may use different common units, but in the specific case of water quality concerns there are very few exceptions. If you were to cite values in molar concentrations you would just confuse and/or annoy everyone.


I don't believe I was proposing that; however, you are correct, I certainly wouldn't want to annoy everyone in the pursuit of knowledge.


> For background, I'm a professional hydrogeologist with a specialization in geochemistry. I've been dealing with water analyses and water quality issues of all types for about 25 years. I've also been keeping aquariums for most of the last 40 years.


I, for one, am sincerely appreciative that this community has someone of your expertise and experience. I've poured over many of your past postings, and find them extremely informative.

Since we're now at the point where professional resumes and accolades are being posted, I will respectfully "cease and desist" so that the original topic of this thread can again be brought to the fore.

My apologies to you and Javalee for pushing this thread off-topic.


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