# [Wet Thumb Forum]-Calcium dosing to increase GH



## dwalstad

I'm continuing Javalee's discussion started in "My newly replanted 10g". He last wrote the following :

"I bought 2 oz. CaCl2 on a brewery website for cheap! I discovered these home-brewery sites are great places to get mineral supplements for plants. They even sell something called Burton's Water Salts that is designed to raise the GH of water used for brewing to the standards of some river water in England that is famous for making good ale. It adds Ca, Mg, and K in the correct proportions and it's cheap if anyone needs to raise GH. The only reason I didn't use it is because using soil packets left me with some spots that I fear could turn anaerobic and the BWS has sulfate in it. I got Epsom salts for Mg. I just dissolved and added them in as close to a 4:1 Ca:Mg ratio as I could."

CaCl2 is probably the best chemical to bring GH up without increasing pH. In my book, I advocated shells, oyster grit, mineral pills, etc. These are all mostly CaCO3 (calcium carbonate). I think they'll work, but they will probably increase the pH.

I highly recommend CaCl2 for calcium dosing. Several lab people that I work with used CaCl2 (upon my recommendations) to bring the GH up in their softwater tanks. Invariably, it stimulated plant growth. I did not recommend CaCl2 in my book, because I didn't think that non-laboratory folks had access to CaClw. However, Javalee seems to have found a good CaCl2 source. I trust beer brewers!









Chloride has no potential for toxicity while nitrate and sulfate salts do. Soil bacteria will convert nitrate to nitrite and sulfate to hydrogen sulfide. Both products are toxic. The amount of chloride you would add to bring GH up doesn't come close to inhibiting plant growth.

Other chemicals like magnesium, iron, etc can be added as sulfate salts, because they are required by plants in much smaller quantities than calcium. (

For folks with soft water tanks, I would go with Javalee's prescription for bringing GH up in softwater tanks:

Add CaCl2 and MgSO4 (Epsom Salts) in a 4:1 ratio (approximately).


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## Dave P

Thank you for posting this Diana! I too have very soft water and have been agonizing over which calcium salt would be most appropriate for aquatic plants in El Natural aquaria. This is much appreciated.

Thanks again,
Dave


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## Endlersmom

Two calcium chloride sources which are available to the public:

Read Labels:

Swimming pool stores: Calcium Up or Water Hardness Powder

Some forms of de-icing salt (Not all are pure.)


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## TWood

> Originally posted by Diana Walstad:
> I'm continuing Javalee's discussion started in "My newly replanted 10g". He last wrote the following :
> 
> " ... I just dissolved and added them in as close to a 4:1 Ca:Mg ratio as I could."
> 
> For folks with soft water tanks, I would go with Javalee's prescription for bringing GH up in softwater tanks:
> 
> Add CaCl2 and MgSO4 (Epsom Salts) in a 4:1 ratio (approximately).


These are two different things. Adding CaCl2 and MgSO4 in a 4:1 ratio by volume will yield a Ca:Mg ratio of about 13:1 in ppm. It's my understanding that a Ca:Mg ratio of 1:1 in ppm is best, which takes a CaCl2:MgSO4 ratio of about 1:3 by volume. See: The Fertilator

CaCl2 is available at: Greg Watson

TW


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## DataGuru

Cool Calculator!

Gotta play with it...

For a 20 gallon tank, it says that if you add 4 grams calcium chloride and 1 gram mag sulfate that will result in 21.15 ppm calcium and 1.3 ppm magnesium.

To get a 4 to 1 ratio of ca to mg in ppm you'd add equal amounts of calcium chloride and mag sulfate.

to get a 1 to 1 ratio of ca to mg in ppm you'd need to add 1 part calcium chloride to 4 parts mag sulfate.

Interesting.


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## javalee

If I had a scale, I personally would have calculated the molar ratio







, but since I don't, I just assumed that Ca+2 and Mg+2, having the same charge, would react in the same way with the reagent in my GH test kit. So I raised the degree of hardness first with Mg, then 4 times that amount with Ca. I may be off on this, but I didn't think my plants would punish me too much if I were.

I'll check out the calculator next time. Epsom salt is hydrated so you would have to include the weight of 7 moles of water per mole of MgSO4.


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## dwalstad

Javalee,

What you've described is (by far) the most meaningful and easiest way to dose with calcium and magnesium. Otherwise, hobbyists will have to become chemists.









(NOTE: this procedure is only needed for very softwater aquariums where GH = 0- 6 _and_ plants aren't doing well)

Steps in Procedure:


Get starting GH of aquarium water

Prepare concentrated solutions of each chemical (MgSO4 and CaCl2)

Add a small portion of Mg solution to the aquarium and measure resulting GH increase

Add Mg solution until you get about what you want (I'd recommend a GH increase of about 1-2, no more)

Then start adding the Ca solution until you get a GH increase that is 4X that of the increased GH due to Mg

The final GH should be over 6, preferably around 8


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## Dave P

It's the 'El Natural' method for dosing calcium and magnesium. Excellent reasoning, Javalee!









Dave


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## imported_sunnysmom

couldn't you use Turbo Calcium? It's a reef product, calcium chloride I think. (Since I happen to have it in the fish cupboard.)

Stacey


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## Dave P

> Originally posted by sunnysmom:
> couldn't you use Turbo Calcium? It's a reef product, calcium chloride I think. (Since I happen to have it in the fish cupboard.)
> 
> Stacey


According to the Kent Marine website, http://www.kentmarine.com/saltwater/tc.html the sole ingredient is anhydrous calcium chloride which is perfect and may be easier for some people to get their hands on.

Thanks for suggesting this, sunnysmom!


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## dwalstad

Thanks everybody for your input on where to get calcium chloride. Big help!


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## aquabillpers

The easiest way to insure that the CA/MG ratio is correct is to use Seachem's Equilibrium. That also contains K and Fe.

Just add the powder and stir.

Bill


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## javalee

Billpers, Equilibrium's ions are all derived from sulfate, i.e. there's a lot of sulfate in each dose; I asked a Seachem rep about this. I think Diana was saying it's best to avoid adding much sulfate, hence the advantage of CaCl2. I already had a high iron content to my water so Equilibrium would have probably initiated an algae bloom. For others who don't have to worry H2S production in the substrate and high iron content, Equilibrium would be much easier.


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## aquabillpers

Hi,

Thanks for your comments.

I have never heard of Equilibrium causing any problems in aquaria. There is always a first time, though.

Compounds containing sulfates are commonly dosed in high tech tanks. K2SO4, MgSO4, and CaSO4 come to mind. I was unable to find any negative comments about sulfates in the APD archives. 

Equilibrium contains very little iron, probably not even enough to remediate any significant deficiency. And many say that excess nutrients in a balance planted aquarium do not cause algae.


Bill


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## dwalstad

Sulfates would generally not cause problems, especially in High Tech tanks with their inorganic substrates.

However, it might cause trouble at high dosages in a tank with a potting soil substrate, which is usually quite anaerobic. Some sulfates would migrate into the soil and could be converted to H2S. The result might be inhibited plant growth.

Equilibrium might be fine for 99% of tanks, but the El Naturale tanks would be the most vulnerable to potential H2S problems. Calcium chloride (CaCl2) doesn't have the potential downside of a product that's loaded with sulfates.


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## aquabillpers

> Sulfates would generally not cause problems, especially in High Tech tanks with their inorganic substrates.
> 
> However, it might cause trouble at high dosages in a tank with a potting soil substrate, which is usually quite anaerobic. Some sulfates would migrate into the soil and could be converted to H2S. The result might be inhibited plant growth.
> 
> Equilibrium might be fine for 99% of tanks, but the El Naturale tanks would be the most vulnerable to potential H2S problems. Calcium chloride (CaCl2) doesn't have the potential downside of a product that's loaded with sulfates.


Not to be disputatious, but I have been using Equilibrium in "el Natural" tanks with some success, for me, anyway.









Is the amount of sulfate contained in Equilibrium considered "high"?

Calcium chloride eliminates "potential" downsides, but it doesn't help to maintain the magnesium level, which is typically done, if needed, with epsom salts, a sulfate.

Since I am using Equilibrium, I would really like some information on problems that it has caused to other users.

Bill


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## Dave P

> Not to be disputatious, but I have been using Equilibrium in "el Natural" tanks with some success, for me, anyway.


Indeed, the use of Equilibrium in 'El Natural' aquariums may not be problematic if the soil underlayer is mostly aerobic. What promotes an anaerobic microbial environment in submerged soils? I would have to think that the following would play a role:

1) Soil depth -- the deeper the soil layer, the greater the propensity for an anaerobic microbial environment.

2) Soil type -- denser soils, I would have to think, would limit the circulation of water throughout the soil layer, promoting an anaerobic environment.

3) Plant root density -- the roots of aquatic plants deliver oxygen to the surrounding rhizosphere. This favors an aerobic microbial environment. Fewer roots would mean smaller and more isolated rhizospheres which would in turn favor the anaerobic environment.

4) Water circulation -- if water circulation is poor in the water column, oxygenated water will have a harder time reaching the soil layer. This would promote an anaerobic environment.

If your aquarium has abundant plant growth with robust root penetration throughout the soil, sufficient water circulation, and a soil layer that is not too deep or too dense, then the use of Equilibrium may pose no problem at all.

However, if your aquarium differs in one or more of these conditions, then there is a greater chance that some of the sulfates contained within Equilibrium will be anaerobically reduced to H2S.

I think Diana was suggesting a solution to people "plagued" with soft water (I can't believe I just typed that...







), which would work regardless of the soil depth, soil type, root density and water circulation.



> Is the amount of sulfate contained in Equilibrium considered "high"?


It's my understanding that *all* of the cationic species (Ca, Mg, Fe, Mn, K) contained in Equilibrium are bound to sulfate. It's nothing but sulfate salts.



> Calcium chloride eliminates "potential" downsides, but it doesn't help to maintain the magnesium level, which is typically done, if needed, with epsom salts, a sulfate.


Since the desirable concentration of magnesium is considerably less than that of calcium, the amount of Epsom's salts needed to achieve this is likewise less. I guess if one was really concerned about limiting the concentration of sulfate, he/she could try to special order MgCl2, but this would be considerably more expensive than picking up a box of Epsom's salts from the drugstore. Alternatively, you could also use a product such as Seachem's Reef Advantage Magnesium, which is a combination of both MgCl2 and MgSO4.

Dave


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## aquabillpers

> Indeed, the use of Equilibrium in 'El Natural' aquariums may not be problematic if the soil underlayer is mostly aerobic.


snip



> If your aquarium has abundant plant growth with robust root penetration throughout the soil, sufficient water circulation, and a soil layer that is not too deep or too dense, then the use of Equilibrium may pose no problem at all.


Thanks for the explanation!

Unless I'm missing something, it would then seem that planted tanks that are set up under Diana's guidelines would tend to have aerobic substrates, at least those that did not use dense soils. Right?

I also don't know how much sulfate would be too much. There are numerous substances in nature that we ingest in small quantities every day without causing us difficulties; the same substances taken in larger quantities would be fatal. I wonder if there is enough in Equilibrium to cause a problem.

Thanks again.

Bill


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## Dave P

> Unless I'm missing something, it would then seem that planted tanks that are set up under Diana's guidelines would tend to have aerobic substrates, at least those that did not use dense soils. Right?


Rather than using the terms 'aerobic' and 'anaerobic', it might be more constructive to define the ideal 'El Natural' substrate as one that possesses a redox gradient that does not exceed ~ -200 mV at it's lowest end. This permits some nice side benefits such as denitrification, manganese solubilization and iron solubilization without fostering conditions that permit the reduction of sulfate. In practice, it's not so easy to achieve this and it doesn't take much to push the redox lower. Many 'El Natural' aquariums (mine included) have areas where sulfate reduction is occuring. Aquatic plants can mitigate this to an extent; however, it wouldn't take much to overwhelm this balance. That's where the concern of having excess sulfate in the water column comes into play. As I've seen over the past few months, one 'El Natural' aquarium can differ quite dramatically from another in ways that are not so obvious. (In my opinion, that's what makes it so much fun!). Soils vary widely which makes it difficult to say "Yes, you can safely use Equilibrium" or "No, you have too much sulfate reduction occurring, Equilibrium's not a good idea". I guess what I'm saying is that for individuals with 'El Natural' aquariums and very soft water, the recommendation for Equilibrium would need to be made on a case-by-case basis, whereas, the recommendation for a mixture of CaCl2 and MgSO4, could be safely made to that audience as a whole.


> I also don't know how much sulfate would be too much. There are numerous substances in nature that we ingest in small quantities every day without causing us difficulties; the same substances taken in larger quantities would be fatal. I wonder if there is enough in Equilibrium to cause a problem.


I too don't know how much sulfate would be too much, but Diana writes in her book that H2S "inhibits root growth or function at a very low concentration..." I also don't know the redox gradient of my substrate although I do know that it must be low enough in some areas to foster some sulfate reduction. I do know that there are large areas of my substrate not occupied by root growth. So I would probably want to err on the side of safety and avoid introducing more sulfates which could be potentially reduced to H2S.

Dave


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## aquabillpers

I enjoy a glass of wine. I brush my teeth with toothpaste that contains flouride. I use sodium chloride on my food. I enjoy an occasional cigar. I know that these things, if done to excess, can lead to health problems.

But I do not worry about that, because I have learned that the chances of anything bad happening from those actions are so remote as to be insignificant.

We do the same thing with out planted aquariums. Some add a little sodium chloride. Others use an antibiotic to kill BGA. Some use high or low temperatures to achieve specific goals. We do those things because they are helpful and we have no evidence that they are harmful if used in moderation.

To me, the same holds true of using Equilibrium to establish calcium and magnesium levels in soft water. It works, it hasn't caused me any problems, and I have not heard of it causing anyone else any.

While sulfur and hydrogen can combine to produce a dangerous and unpleasant gas, I don't know if the small amounts added by Equilibrium are at all significant to that process. I am an agnostic as far as that is concerned.

I have asked Seachem for their opinion. I also invited them to post to this thread if it suited them. So we'll see what happens.

Uh, what are those bubbles coming from that substrate over there? Hmmmm.









Bill


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## Dave P

> While sulfur and hydrogen can combine to produce a dangerous and unpleasant gas, I don't know if the small amounts added by Equilibrium are at all significant to that process. I am an agnostic as far as that is concerned.


By my estimates, there is approx. 0.57 g of sulfate -- over half a gram -- in every gram of Equilibrium. If one follows the label, raising GH by 3 degrees would require the addition of 16 grams (1 tablespoon) of Equilibrium for every 20 gallons of water. Using the above figure, this would mean that 9 of those 16 grams is sulfate. In my opinion, this is not a small amount.

I do agree, however, that more research on this issue would be desirable, and that it would be interesting to see what Seachem would have to say.

Dave


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## dwalstad

> Originally posted by Dave P:
> 
> By my estimates, there is approx. 0.57 g of sulfate -- over half a gram -- in every gram of Equilibrium. If one follows the label, raising GH by 3 degrees would require the addition of 16 grams (1 tablespoon) of Equilibrium for every 20 gallons of water. Using the above figure, this would mean that 9 of those 16 grams is sulfate. In my opinion, this is not a small amount.
> 
> Dave


Hardwater in nature contains bicarbonates, sulfates, and chlorides. Wetzel (_Limnology_, p. 183 of his 1983 edition) shows the sulfate concentration between 17 and 35 mg/l (the chloride range is 8 to 17 mg/l) of five naturally hardwater lakes. Just for fun, I'm going to follow up on Dave's post, to see how his Equilibrium addition compares to the sulfate concentration in these natural hardwaters.

20 gal X 3.8 liters/gal = 76 liters

If naturally hardwater contains 35 mg of sulfates/liter, the tank contains a total of 2,700 mg (35 mg sulfates/liter X 76 liters). And 2,700 mg = 2.7 g. This is less than the 9 grams of sulfates added by Equilibrium dosing to get a GH increase of 3 (according to Dave's calculations).

Adding a CaCl2/MgSO4 combination better mimics the natural condition of having a mixture of anions, not just one. It also lessens potential H2S problems. Potting soil substrates, at least mine, have been quite anaerobic (fresh ones bubble like mad for months). I am fairly sure that they have a Redox low enough for H2S production.

That said, I have never heard a single complaint about Equilibrium, and many hobbyists defend it vigorously.


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## Dave P

Thank you Diana for posting this data on sulfate and chloride concentrations found in hardwater lakes. I just might use some of my upcoming vacation time to visit the university library nearest me and find this study that Wetzel published in Limnology.

If anyone is interested in how I determined how much sulfate is present per gram of Equilibrium, please leave me a PM with an email address and I will gladly send you a Word doc showing the stoichiometry and results. If I had more time, I'd make the document look prettier than it is; however, it is quite legible in it's present state.

Dave


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## aquabillpers

This thread is extremely interesting to me, in part because it is bringing back long forgetting memories of moles, molecular weights, and similar, personally-unused concepts and, in part, because it does present evidence that supports the possibility that Equilibrium can cause problems. But I remain an agnostic on that.

One question that I have is, what happens to the SO4 when it splits from the CA? I suspect that it undergoes further changes, rather than just sinking into the substrate. Some of it is undoubtedly absorbed into plant tissue; perhaps some combines with other chemicals and becomes insoluble. I don't know.

While walking through swamps I've often encountered large amounts of H2S. (It can be easily identified without expensive lab equipment.







I wonder if high sulphates in the water by themselves are responsible for this or if there is some other process involved that grabs whatever sulphur is available to combine with the hydrogen. I don't know that, either.

It would be interesting to conduct an experiment with two natural tanks with anaerobic substrates and water with low sulfates. CaSO4 would be added to one and the amount of H2S measured. The point at which H2S becomes a threat would also have to be predetermined.

Bill


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## aquabillpers

Here's Seachem's reply to my question. It seems to support both views, which is good, since both
are "right".

"Dear *****,

As Diana Walstad said, in the vast majority of tanks Equilibrium is fine to use. Theoretically a tank with a large amount of anaerobic areas could have problems with hydrogen sulfide production. In her book she also mentions that oxygen released by the roots and soluble iron give the plants some protection. We have not experienced this problem nor have we had any reports from customers on this problem.

Best Regards,
Seachem Tech Support~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Seachem Laboratories, Inc. http://www.seachem.com 888-SEACHEM
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


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## dwalstad

> Originally posted by Billpers:
> 
> Q #1: One question that I have is, what happens to the SO4 when it splits from the CA?
> 
> ***Plants will take up some sulfate for their sulfur needs (they need almost as much sulfur as magnesium). See "Critical Concentrations" on page 105 in my book.
> 
> The remaining sulfate diffuses throughout the water. I don't know of any sulfate salt that is insoluble. That's why Equilibrium probably dissolves very quickly. Dissolved salts (including sulfates) will diffuse into the substrate so that the concentration in substrate water will probably approximate what's in the water.
> **************
> 
> While walking through swamps I've often encountered large amounts of H2S. (It can be easily identified without expensive lab equipment.
> 
> 
> 
> 
> 
> 
> 
> I wonder if high sulphates in the water by themselves are responsible for this or if there is some other process involved that grabs whatever sulphur is available to combine with the hydrogen. I don't know that, either.
> 
> ***Bacteria use sulfates as their electron acceptor and convert the sulfates to sulfides (reaction on p. 67 my book). The sulfides readily combine with metals in soil like iron, zinc, manganese, etc to form precipitates. If there's no metals to precipitate out the sulfide, then you have H2S. That's why I got major toxicity when I added sulfate-contaning fertilizers to potting soil (made up mostly of organic matter and with very little metals), but got absolutely no toxicity when I added same fertilizer to my garden soil.
> 
> Brackish water swamps along the coast will have more H2S than freshwater swamps that are further inland. That's because ocean water contains lots of sulfates.
> **********
> 
> It would be interesting to conduct an experiment with two natural tanks with anaerobic substrates and water with low sulfates. CaSO4 would be added to one and the amount of H2S measured. The point at which H2S becomes a threat would also have to be predetermined.
> 
> Bill


Experiments are always fun. I would compare CaSO4 with CaCl2 (OR MgSO4 with MgCl2). The only variable then is the sulfate.

I was pleased with Seachem's response to your query. Thank you for posting it.


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## javalee

I just wanted to update everyone interested in Ca++ Mg++ supplementing. I raised the GH of my 10g from 3dGH to 9dGH with CaCl2 and MgSO4 (epsom salt) thinking I would rarely have to add it again. However, I've noted that the plants must be sucking the Ca++ and Mg++ out of the water at a pretty good rate. Within 2 weeks of the first addition the GH was back down to 6 or 7. This week I checked and it was down to 4dGH! 

So I'm adding it about every two weeks now. Of course, I just top of evaporation loss with tap water, and when doing water changes (which I'm doing more of than most natural tank people do lately as the DOC leach out of the soil) I replace with 8dGH water.

It's not a bad regimen as I've memorized about how much to add to get the 4:1 ratio of Ca++ and Mg++. I can usually test it and get the right amount within two tries. The fact that it's disappearing makes me think my plants are better off for getting an ample supply! The hornwort is finally growing as hornwort should---requiring thinning 2xs per week!

Below is a picture after serious thinning and pruning of hornwort, floating plants, and hygro.


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## dwalstad

Javalee,

What a gorgeous tank! You must be very pleased.

I think that some of the water calcium precipitates out (as calcium phosphate, calcium carbonate, etc). Scientists that analyzed filter biofilm contents found calcium phosphate and other precipitated salts in the filter gunk. Also, some precipitated calcium may end up in the substrate. None of this will hurt anything and probably will help.

In any case, the dosing you're doing is clearly working.


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## javalee

Thanks so much Diana! I am very pleased with your method! It never even occurred to me that the ca++ and Mg++ could be precipitating. Thank you for explaining that. I wonder if I should still be adding it? I guess if it's not measurable it's not available to plants? I don't know, but yes, the plants are doing well!


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## DataGuru

Here's a good thread on Koivet where Roddy Conrad explained the chemistry behind how calcium and magnesium help stabilize pH and what happens when it precipitates out. In the example they were talking about a pond with an algae bloom and low GH had pH spiking very high even tho KH levels were fine.


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## javalee

Thanks for the link Betty. I like Koivet as a disease resource but would've never found that explanation. I do have a KH of 20d despite my 0dGH tap water so I guess I'm getting calcium carbonate ppt. With a pH of 8-8.6, I wonder if most of the Ca and Mg that is "disappearing" from my GH test is being sequestered from the plants that way.


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## dwalstad

Once again, we can all learn something from the pond folks. Thanks Betty! I hadn't thought about adding Ca and Mg to control pH swings. Interesting.


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## DataGuru

Definitely! It's amazing just how complicated water can be! LOL


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## Jane of Upton

This is a great thread!

Always one to comparison shop, the price of CaCl varies widely.

Most expensive, I found Turbo Calcium at Doctor's Foster & Smith for $15.99 for 800 g. (1.76 lbs). That's $9.08 per pound.

Next was a home brewer site (Perfect Brew Supply), at $2.90 lb 

Least expensive was GregWatson.com, charging $2.17 per pound.

Of course, I didn't calculate in shipping, but it was very interesting to see the spread of prices!

-Jane


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## javalee

Jane, I thought that buying from NorthernBrewer.com was great because I could buy only 2 ounces instead of a pound of the stuff! Of course, I only have a 10g tank.

Oddly enough, I measured today and the GH is down to 3dGH again! Nothing is ever simple in a natural aquarium!


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## flagg

Ok so I went ahead and finally read through this entire thread since I tested my water this afternoon and noticed that my GH had gone down to 0-1 dGH. I checked my Aquarix log and saw that the GH in this tank was at 8dGH on 10/26/05. So there's obvious been a steady decline and I should have seen this coming for the dGH was at 12 on 10/05. So the first thing I learned is that I should be testing my water more often! I'm pretty sure that I've tested the hardness in this tank since then, but don't really remember... Anyhow.... since reading this thread my head's still spinning and I just want to recap what my options are. As I see it, I have two:

1. add CaCl2 and MgSO4 in the manner describe above to achieve a 4:1 ratio and a dGH of around 8, OR
2. use Seachem's Equilibrium per their instructions to raise the GH to around 8.

All things aside, can I assume that it just comes down to a matter of preference?

One last thing, Diana mentioned to raise the GH if the plants are not growing well and the GH is low. My plants appear to be growing quite well, should I even bother?

-ricardo


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## Dave P

Ricardo,

_Are_ all of your plants growing well? Didn't you recently have some H. polysperma that had holes in its leaves?

I seem to recall that you placed some cuttlebone in your substrate a while back, primarily for your Vallisneria. Perhaps the other plants are benefiting from this as well.

If your plants are truly growing well and the snails are not showing signs of calcium deficiency (weak shells), then perhaps you do nothing and just keep an eye on things.

Having said that, I believe many aquatic plants possess mechanisms to store some nutrients for leaner times. Perhaps your plants are currently living off of what they've accumulated over the past couple of months. If that's the case, these nutrient stores may become drained over the next month or so.

The last paragraph is speculation on my part and could be completely wrong; validation would be most helpful.

As far as which method should be used to raise GH, that needs to be your decision. I personally favor water with a mixture of anions over something that has a larger sulfate ratio. But that is conjecture; more experimentation is necessary. I think this thread does a pretty good job of illustrating the potential pros and cons of either method.

Just my thoughts,

Dave


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## dwalstad

> Originally posted by Ricardo V.:
> 
> One last thing, Diana mentioned to raise the GH if the plants are not growing well and the GH is low. My plants appear to be growing quite well, should I even bother?
> 
> -ricardo


Dear Ricardo,

If your plants are doing well, then I would relax and just enjoy your aquarium. If new plant growth becomes poor, then you can _officially_ start to worry. The nice thing about plants is that they're on a slow time table; there's plenty of time to remedy potential problems.


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## dolce_ardore

*Use of Seachem Equilibrium*

This is a very interesting and informative thread. Thanks to all for contributing.

I live in an area with <2 dGH water and very recently being trying to determine the best way to increase it to approach the recommended value of 8 dGH.

My first attempt has involved adding enough Seachem Equilibrium as per the product instructions to raise the dGH by 6 degrees, which for my 25g tank (let's say 20g water net) I estimated to be 32g (each 16g is said to increase dGH by 3 degrees in 20g of water). However, I lated discovered, based on other information such as the "FertFriend" tool, I've added the following nutrient concentrations:

62.4 ppm K >> [10-20]
25.792 ppm Ca ~ [10-30]
7.712 ppm Mg > [2-5]
0.352 ppm Fe >> [0.1]
0.192 ppm Mn​
where the numbers in brackets are the recommended ranges, taken from Fertilator.

It's evident that the stated level increases from adding Equilibrium are far higher than the recommended ranges, with the exception of Ca, assuming all nutrients are added in the appropriate forms. It would therefore seem, on the surface of it, that using Equilibrium to increase dGH by more than a few degrees can cause a significant nutrient surplus, which may or may not have negative effects.

I also believe there was an increase in my pH, presumably due to an increase in KH, though I didn't measure pH and KH immediately before adding the Equilibrium. In a CO2 tank having the pH go up due to increased KH is fine since it will be brought down again by the CO2, but in a non-CO2 tank such as mine, an increase from my tapwater's nominal pH of 7 is not desirable.

These observations would seem to suggest that following Diana's method for increasing GH is better than simply using Equilibrium.

Further on the subject of CO2, I am wondering something else... To what degree will the addition of the Equilibrium detract significantly from the accuracy of calculating CO2 concentration from pH and KH using a standard table/graph (due to unaccounted buffering)? What about Diana's suggested method of adding only CaCl2 and MgSO4?

David


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## DataGuru

Interesting info. 
Dunno on the Equilibrium, however, adding calcium chloride and mag sulfate shouldn't affect being able to derive CO2 levels from pH and KH.


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## CraigThor

Diana I wonder if you or anyone is still using CaCL2 for adjusting there tanks.

I have 2 lbs of CaCL2 and am wantign to use this method to avoid a PH increase.

I know this is an old post but seems to have alot of good info.

Craig


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## Seattle_Aquarist

Hi CraigThor,

I use CaCl2 for my tanks and have no problems. I know some people have expressed concern about the chloride being a problem for the fish or plants, but I have not experienced any problems using it.

I tried CaSO4 and CaCl2 and found I liked CaCl2 better because it dissolves clear while CaSO4 was "milky". One warning if using CaCl2, the chemical reaction with water is quite strong and generates heat. Add the CaCl2 to water, do not add add water to CaCl2; and do not be surprised if the glass you are mixing it in becomes warm. I would not add CaCl2 directly into my tank for fear the fish might try to eat the crystals before they dissolved.


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## CraigThor

Seattle_Aquarist said:


> Hi CraigThor,
> 
> I use CaCl2 for my tanks and have no problems. I know some people have expressed concern about the chloride being a problem for the fish or plants, but I have not experienced any problems using it.
> 
> I tried CaSO4 and CaCl2 and found I liked CaCl2 better because it dissolves clear while CaSO4 was "milky". One warning if using CaCl2, the chemical reaction with water is quite strong and generates heat. Add the CaCl2 to water, do not add add water to CaCl2; and do not be surprised if the glass you are mixing it in becomes warm. I would not add CaCl2 directly into my tank for fear the fish might try to eat the crystals before they dissolved.


Thanks. The Chloride is what I was wondering about. I've been told by several not to use it because of too much chloride.

I also did order some CaSO3/4 dont remeber which from Aquariumfertilizer.com also. I will be using it in my shrimp nanao tank as a form of calcium for the shrimp and snails

Craig


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## dwalstad

CraigThor said:


> Thanks. The Chloride is what I was wondering about. I've been told by several not to use it because of too much chloride.
> 
> I also did order some CaSO3/4 dont remeber which from Aquariumfertilizer.com also. I will be using it in my shrimp nanao tank as a form of calcium for the shrimp and snails
> 
> Craig


I do not recommend adding sulfates to NPTs, especially those with a potting soil or organic substrates. H2S generated from sulfates in the anaerobic environment is highly toxic to plant roots.

Chloride is only inhibitory in massive amounts, much less than what you need to add for increasing water hardness. For example, to bring GH up to my water's hardwater levels, you would need to add 30 ppm of CaCl2. This addition would bring with it 60 ppm of chloride. This is 60 mg/l, which is only 0.006% chloride. Plants are inhibited by salt (sodium chloride) at 0.1%.

Bottom Line: The amount of chloride you're adding to get GH up to increase water hardness is much less than what would inhibit plants.

If you have a clay or gravel substrate with no organic matter, CaSO4 will probably cause no problems. But in an NPT with an organic soil, you risk getting reduced plant growth and other problems.


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## CraigThor

dwalstad said:


> I do not recommend adding sulfates to NPTs, especially those with a potting soil or organic substrates. H2S generated from sulfates in the anaerobic environment is highly toxic to plant roots.
> 
> Chloride is only inhibitory in massive amounts, much less than what you need to add for increasing water hardness. For example, to bring GH up to my water's hardwater levels, you would need to add 30 ppm of CaCl2. This addition would bring with it 60 ppm of chloride. This is 60 mg/l, which is only 0.006% chloride. Plants are inhibited by salt (sodium chloride) at 0.1%.
> 
> Bottom Line: The amount of chloride you're adding to get GH up to increase water hardness is much less than what would inhibit plants.
> 
> If you have a clay or gravel substrate with no organic matter, CaSO4 will probably cause no problems. But in an NPT with an organic soil, you risk getting reduced plant growth and other problems.


Diana,

Thanks. My tank is actually a high tech tank but I'm trying to eliminate any ph swing that adding chemicals can occur as its also my shrimp tank. I added about 3/4 tsp of both MgSO4.7H2O and CaCL2 to get my tank 5g up to where I want it atleast by the math (also by the fertilator) no test kit yet. I use the ADA Aquasoil in my tank with pure RO water and needed to add Ca and Mg for my shrimp and snails.

I had a chat with Ray Lucas (Kingfish Services) this weekend and he told me he had done a talk on NPT and was fortuante enough to meet you afterwords.

Thanks for posting your input as everyone is telling me that the Chloride is harmful for the tank. I have 2 lbs of it so I would love to use it.

Craig


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## colinsk

If you are using RO water I would consider CaCO3 instead of CaCl.


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## CraigThor

colinsk said:


> If you are using RO water I would consider CaCO3 instead of CaCl.


Any reasoning behind that?


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## colinsk

Any slight addition of H+ in the water will make large pH swings unless you have some kH (alkalinity, carbonates, CO3, for this discussion we can consider them the same). An RO unit removes almost all of the kH. Normal biological processes tend to want to swing the pH lower and having some CO3 as a buffer is a good idea to keep your tank from swinging pH. In a few hours you could go from 6 to 5 pH. I prefer to run around 7 and have both fast and slow buffers in the tank. I use CaCO3 as a fast buffer (from my tapwater) and oyster shells as a slow buffer. This gives me time to notice a problem before it is a big problem. I still keep my kH fairly low at 4 but it is much better than 0.


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## dwalstad

I have no problem with either CaCl2 or CaCO3. However, Colinsk has a good point. If you have R.O. water, it probably doesn't have any bicarbonates. You could use CaCO3 to add bicarbonates to the water and increase the buffering capacity. However, the easiest thing to do would be to add baking soda (sodium bicarbonate) to get KH up and CaCl2/MgSO4 to get GH up. 

Here, we realize that its tough to duplicate hard water with its main ingredients, which are: bicarbonates, calcium, magnesium, and potassium. These are all major plant nutrients and pH buffers. On page 87 of my book, I suggest additions for those with ultra-soft water. 

I don't advocate using R.O. water for planted tanks unless there's a real and identified toxin that you have to remove. Why remove all the natural hardwater salts and then have to put them all back later on?


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## colinsk

dwalstad said:


> Here, we realize that its tough to duplicate hard water with its main ingredients, which are: bicarbonates, calcium, magnesium, and potassium. These are all major plant nutrients and pH buffers. On page 87 of my book, I suggest additions for those with ultra-soft water.


At work I have to do this everyday. I have to emulate the brewing waters of the world. I have a very good spreadsheet and lots of acids and salts. I would rather start from tap water but I also can start from RO or DI water if I need to. I would not choose to do this with fish. If my water was very hard, like from the Great Salt Lake, then I would dilute with RO but starting from scratch is very hard.


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## barbarossa4122

Hi,

Can cacl2 precipitate by itself? I am asking b/c my cacl2 solution has a "lemonade" or very light tea color and also, I have to shake the bottle every time I am dosing.
What can cause this? I mixed it with Poland Spring bottled water, that's it. (220 grams in 1L water) I bought the cacl2 from AquariumFertilizer. OK to keep using this solution? Btw, this is the second time I made cacl2 solution and both times the same thing happened.


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## dwalstad

barbarossa4122 said:


> Hi,
> 
> Can cacl2 precipitate by itself? I am asking b/c my cacl2 solution has a "lemonade" or very light tea color and also, I have to shake the bottle every time I am dosing.
> What can cause this? I mixed it with Poland Spring bottled water, that's it. (220 grams in 1L water) I bought the cacl2 from AquariumFertilizer. OK to keep using this solution? Btw, this is the second time I made cacl2 solution and both times the same thing happened.


I doubt that minor impurities like this will cause any problems. The calcium chloride may not be ultra-pure (ultra-purity not needed for fertilizer use) or the calcium is reacting with something in the spring water.

When you dose your tank, you will dilute this very concentrated solution (_at least _1:5,000). Whatever minor contaminants are in the stock solution will then be diluted out to insignificance.


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## barbarossa4122

dwalstad said:


> I doubt that minor impurities like this will cause any problems. The calcium chloride may not be ultra-pure (ultra-purity not needed for fertilizer use) or the calcium is reacting with something in the spring water.
> 
> When you dose your tank, you will dilute this very concentrated solution (_at least _1:5,000). Whatever minor contaminants are in the stock solution will then be diluted out to insignificance.


Hi,

I solved the problem. The bottle I used before was contaminated. Thanks for the info Diana.


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