Controlling pH with calcium carbonate

[Catfishnut]

I am curious so I thought I would ask.

I have read posts here and info on websites for pond equipment and support regarding using oyster shells for the CaCO3 (calcium carbonate) to passively maintain the pH balance in the pond.

How do oyster shells compare to other sources of CaCO3 like chicken eggshells, limestone, calcite and marble?

Are there any drawbacks to using any of the other major sources of CaCO3?

Are there any major benefit to using Oyster shells over the others?

My reasoning is that the limestone and calcite are readily available here at a low cost for a large quantity.

Marble is also readily available, but more expensive and I would think that it would be more stable and not as well suited for the purpose (as I don't think it would leach away fast enough to act on pH control in this application). I may be wrong on that assumption, so that is why I am asking these questions.

My idea was to utilize calcite as a component of my preconditioning for a B.I.R.M. filter unit to remove iron from my well water. This is recommended by the B.I.R.M. media manufacturer CLACK Corp. for the purpose of adjusting the ph so that the B.I.R.M. media works best and according to specifications.

I comprehend the chemistry of this all well enough, but I don't know about how tightly the CaCO3 is locked up in each of these sources. I assume that marble would be the least likely to leach out is CaCO3 into the water or the slowest if you want to put it that way. Then calcite, and the limestone would be the mjost likely to leach out quickly. But, I don't know where the oyster shells would fall into this order.

Obviously the leaching of the CaCO3 into the water would also depend upon the mesh size of the rock or shell.
The finer the particle, the more surface area available to be in contact with the water, so that is another point.

How do Oyster shells that you use for your pond come? Are they whole, broken, crushed into small pieces or are they pulverized into chips or even a coarse powder-like form?

if you have any input on this subject, I would appreciate it.

Gordy

 

[sissy]

tractor supply here is crushed somewhat fine but tulle or 2 dollar store bags handle it fine .I would say it is close to the fineness of kitty litter .All I can think to compare it too .You can get courser ground if you order it but for me the fine has worked .Remember chickens eat it to make the eggshells harder for shipping so the have to be able to eat it

 

[Catfishnut]

Sissy,

I forgot to check with TSC. I am sure that they would definitely have oyster shell at their store here.
If it is ground up, that would be best, it is more akin to what I am looking for.

Thanks

 

[crsublette]

1) How do oyster shells compare to other sources of CaCO3 like chicken eggshells, limestone, calcite and marble?

It would not be too different. It all depends on how those are products are manufactured and the extent of impurities in those other products.


2) Are there any drawbacks to using any of the other major sources of CaCO3?

Refer to point #1.


3) Are there any major benefit to using Oyster shells over the others?

Refer to point #1.

Now, there are medicated oyster shell products out there that also contain fish probiotics or other medicinal properties. These are more often used in aquariums, but I would be cautious when using these.


4) My reasoning is that the limestone and calcite are readily available here at a low cost for a large quantity.

Marble is also readily available, but more expensive and I would think that it would be more stable and not as well suited for the purpose (as I don't think it would leach away fast enough to act on pH control in this application). I may be wrong on that assumption, so that is why I am asking these questions.

Refer to point #1.


5) I comprehend the chemistry of this all well enough, but I don't know about how tightly the CaCO3 is locked up in each of these sources. I assume that marble would be the least likely to leach out is CaCO3 into the water or the slowest if you want to put it that way. Then calcite, and the limestone would be the mjost likely to leach out quickly. But, I don't know where the oyster shells would fall into this order.

That is the crux of it. It would depend on the impurities in the crystal formations and if these impurities impede the CaCO3 from dissolving.

Aragonite, oyster shells, coral, calcite, limestone, marble, and many others are out there, but this mainly refers to the crystal formation and the potential for other impurities in the formation. The impurities could be beneifical trace minerals or other byproduct of decomposing plant/marine life or the impurities could be the result of how the crystal formation was manufactured.

It is like the difference between drinking bottled water and water that comes from your house's spigot. Your body reacts the same to either type of water, since it is still H2O, but the house's spigot water might have different attributes or impurities in it when compared to the bottled water and vice versa.


6) Obviously the leaching of the CaCO3 into the water would also depend upon the mesh size of the rock or shell.
The finer the particle, the more surface area available to be in contact with the water, so that is another point.

You got it. That is exactly right.


7) How do Oyster shells that you use for your pond come? Are they whole, broken, crushed into small pieces or are they pulverized into chips or even a coarse powder-like form?

Due to the exact same reason you mentioned in point #6, I would do crushed or flaked oyster shells, which is what they feed to chickens. When crushed or flaked, then it is easier to put the product in a water filter without the concern of clogging such as if it was in powder form. Also, the product being in powder form does not ensure it will all dissolve into the water, but it does increase the likeliness of it happening. The problem with the powder form is that it is easier for water changes to remove the calcium carbonate out of the water, which then defeats one of the purposes of using a calcium carbonate product, that is to remain in the water until it is needed.

In the context of the CaCO3 used for chickens, be sure to carefully read the product since some of these products will have other supplements in it to help the chickens and you just want nearly 90~99% pure CaCO3.

I am curious so I thought I would ask.

I have read posts here and info on websites for pond equipment and support regarding using oyster shells for the CaCO3 (calcium carbonate) to passively maintain the pH balance in the pond.

1) How do oyster shells compare to other sources of CaCO3 like chicken eggshells, limestone, calcite and marble?

2) Are there any drawbacks to using any of the other major sources of CaCO3?

3) Are there any major benefit to using Oyster shells over the others?

4) My reasoning is that the limestone and calcite are readily available here at a low cost for a large quantity.

Marble is also readily available, but more expensive and I would think that it would be more stable and not as well suited for the purpose (as I don't think it would leach away fast enough to act on pH control in this application). I may be wrong on that assumption, so that is why I am asking these questions.

My idea was to utilize calcite as a component of my preconditioning for a B.I.R.M. filter unit to remove iron from my well water. This is recommended by the B.I.R.M. media manufacturer CLACK Corp. for the purpose of adjusting the ph so that the B.I.R.M. media works best and according to specifications.

5) I comprehend the chemistry of this all well enough, but I don't know about how tightly the CaCO3 is locked up in each of these sources. I assume that marble would be the least likely to leach out is CaCO3 into the water or the slowest if you want to put it that way. Then calcite, and the limestone would be the mjost likely to leach out quickly. But, I don't know where the oyster shells would fall into this order.

6) Obviously the leaching of the CaCO3 into the water would also depend upon the mesh size of the rock or shell.
The finer the particle, the more surface area available to be in contact with the water, so that is another point.

7) How do Oyster shells that you use for your pond come? Are they whole, broken, crushed into small pieces or are they pulverized into chips or even a coarse powder-like form?

if you have any input on this subject, I would appreciate it.

Gordy

 

[Catfishnut]

Charles,

Your assesment appears to be right in line with what I was thinking from the start. This allows me some freedom to experiment and be creative with the application as I can use all sorts of the CaCO3 sources to fit the specific task.

For instance, I could use whole or partially broken oyster shells as a layer of media in a biological converter chamber or possibly a bakki shower. The bacteria colonies could grow upon the shells and the irregular physical dimensions of the shells would allow for free-flow of water throughout the media thus supplying the bacteria with oxygen and constant water flow carrying oxygen, ammonia and nitrites through it. The CaCO3 would also slowly (probably very slowly) leach out of the shells over time and that would assist in automatically controlling the pH.

A sand/gravel type polishing filter (or even a bog) could utilize crushed marble, calcite and limestone and pulverized oyster shell amongst the layers of pea gravel and sand and maybe even some zeolite. This could serve as both a mechanical filter and a bio-filter converter, too.

Large chunks of marble or limestone could be used in the pond construction for ornamental and aesthetic purposes, but also serve to supply CaCO3 to a limited extent.

Do you envision my strategy here? I could have many sources of CaCO3 in various areas of the pond and its filtration systems and each source would be providing more utility than just controlling the pH. They would serve other functions too, and a side effect would be assisting in passively controlling the pH.

Gordy

 

[addy1]

Great write up Charles.

Gordy I use the crushed oyster shells for chickens. I do not rinse them off, just toss 100 lbs on top of my bogs pea gravel, a cloud of dust comes off which disappears in a few hours. Doing this has kept my pond's ph around 7.6 and the hardness near 100. I add the 100 lbs every spring. By fall most of the shells are gone.
Our well water is 5.4 with almost zero in hardness, during the summer I have to add water every day, which can drive hardness and ph down.

 

[crsublette]

Gordy, give Capewinde a private message. Her husband works in the pond maintenance arena and uses a special formulation of aragonite that they believe is better balanced and dissolves quite well. I can't remember the name of the product off hand without some google searching for it. Also, it might be worth looking into, but, if it is too expensive, then the typical stuff is just fine enough.

Lithaqua is another very nice product made out of calcified algae and is chalk full of quite robust beneficial trace minerals that significantly boost the nitrifying microorganisms, but I do not think it is available in the US of A anymore since the European distributor can't find anyone to buy enough in bulk to justify the overseas shipment cost. It might be worth googling.


I think it is always good to use a calcium carbonate product in bogs or pots or streams or filters due to the inorganic carbon it can release to feed the microorganisms. Of course, if the pH gets near 8.3, then it becomes useless since it stops dissolving, but, if eventually the pH were to ever fall, then it will be available to dissolve.

Also, there are zones where the pH will be lower than the actual water such as the microscopic area around the microorganism's bio-film or in pots or bogs. So, as the pH drops in these zones, then the product will release its carbonate goodness.

Remember, there will always be a bio-film formed around the product irrelevant of where the product is placed so this may impede the dissolve rate of the product, but this is unavoidable and even in high water flow areas it is still unavoidable.

Ultimately, the pH and product volume presence in the system will determine the degree of impact the product has on the system, but, even if it just a little while the pH is relatively high, I do not see any harm in using the product and it would be a better product to use instead of sterile kitty litter or pea gravel or any of the other sterile aggregate mediums.

Charles,

Your assesment appears to be right in line with what I was thinking from the start. This allows me some freedom to experiment and be creative with the application as I can use all sorts of the CaCO3 sources to fit the specific task.

For instance, I could use whole or partially broken oyster shells as a layer of media in a biological converter chamber or possibly a bakki shower. The bacteria colonies could grow upon the shells and the irregular physical dimensions of the shells would allow for free-flow of water throughout the media thus supplying the bacteria with oxygen and constant water flow carrying oxygen, ammonia and nitrites through it. The CaCO3 would also slowly (probably very slowly) leach out of the shells over time and that would assist in automatically controlling the pH.

A sand/gravel type polishing filter (or even a bog) could utilize crushed marble, calcite and limestone and pulverized oyster shell amongst the layers of pea gravel and sand and maybe even some zeolite. This could serve as both a mechanical filter and a bio-filter converter, too.

Large chunks of marble or limestone could be used in the pond construction for ornamental and aesthetic purposes, but also serve to supply CaCO3 to a limited extent.

Do you envision my strategy here? I could have many sources of CaCO3 in various areas of the pond and its filtration systems and each source would be providing more utility than just controlling the pH. They would serve other functions too, and a side effect would be assisting in passively controlling the pH.

Gordy

 

[crsublette]

I just did a quick search for some Lithaqua. It is a shame it is not available in the US of A anymore. All the normal distributors that I go through no longer sell it. Good thing I made a bulk purchase of the stuff while they were still selling, but, unfortunately, I only have 1x 50lb. bag left over that might last me for 6 months. Sorry to say that this is really disappointing this product is not available anymore. It was the best that was out there.

I think the next choice in line might be the special formulations of aragonite products, which can be a bit expensive as well.

 

[Catfishnut]

Aragonite was one of the resources on my list, but I really did not know what it was. I wil have to do some research on that to learn more. I always enjoy the experience of learning. I start out to research one item and then I find myself 500 miles off the initial topic looking up something else and discovering new information that I didn't even know I was interested in! Awesome!

Lithaqua is a mineral (substance) that I had never heard of before. i guess if it is hard to obtain now or no longer available, I'lll just have to do without..but I will look it up regardless.

Gordy