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

 

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.)

 

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

 

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.

 

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.

 

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

 

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

Dave

 

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

 

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!

 

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

 

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

 

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.

 

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

 

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.

 

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

 

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

 

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

 

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

 

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

 

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

 

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.

 

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

 

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

 

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
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

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.