# Increasing GH with Wonder Shells



## dwalstad (Apr 14, 2006)

For those living in NYC, Seattle, Raleigh, etc where water is ultra soft (GH = 0-2), Wonder Shells may be an easy and fast way to increase water hardness. Not only that, but the shells reportedly contain other nutrients associated with hardwater (Mg, K, S, B, etc). This is a bonanza for plants. Others on this forum have seen increased plant growth and I’m not surprised.

Even though my water is moderately hard this time of year, I went ahead with a little study. 

I added just one small Wonder Shell from a (~$2/pkg) to a 5 gal tank. Manufacturer recommended adding 3 of these shells to a 5 gal tank, but I figured that was way too much. 

GH increased from 6 to 15 within just 10 days and much of the shell dissolved. Note that I did not have water movement in this 5 gal tank and the shell was just sitting in a corner. If I had put 3 shells as recommended by manufacturer into a 5 gal tank with water movement and a lower starting GH, it would have sent the GH off the charts!

KH decreased a little, so those starting out with zero KH may need to add a little NaHCO3 via baking soda. (Find a cheap generic baking soda brands that is pure sodium bicarbonate. If the baking soda increases GH, then you know it contains calcium, and therefore, is not pure NaHCO3.)

Photos show picture of shells, pH/GH/KH results, and my 5 gal tank 10 days after first adding shell.




























Wonder Shells


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## ronnie (Feb 26, 2021)

_Edit: I have contacted the company asking about how many small shells equal other sizes. I’ve also asked for any other information or data they would be willing to share to us._ _I spoke of our own data collection and discussion hoping it would lead to new info. 

——_

Thank you so much for starting this thread. I can’t wait to see the data pile up.

Something I haven’t been able to find is how many small wonder shells equal a large, etc. I have deduced that 3 small = 1 large (approx), but it is unclear.

It is also recommended not to place wonder shells in a filter, but to only be dropped in the tank.

They also advise beginning with one quarter (1/4) of the dose and work up from there as to not cause sudden changes that may stress the fish and plants.

It is also noted that a 10% increase in GH after a few days indicates a safe dosing amount.

More info

*Manufacturer dosing recommendations:*
Quart - 1 small
Gallon - 2 small
5 gallon - 1 large
10-20 gallon - 1 super size
Larger than 20 or a pond - 1+ giant size.

*Manufacturer claims:*

Instantly removes chlorine and chloramine
Clears cloudy water
Increases the ratio of dissolved oxygen and minerals (theoretically allowing greater stocking options)
Stronger shells for snails/inverts
Mystery snails more apt to reproduce
Fish may spawn more readily


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## dwalstad (Apr 14, 2006)

I agree with manufacturer on not putting shells in a filter. Water movement will greatly speed their dissolution. My one little shell (*1/3 the recommended dose*) sitting in a stagnant corner of a 5 gal dissolved plenty in 10 days. The 9 degree GH increase was generous. As the shell remains continues to dissolve, I am definitely glad I did not add any more shells!

Water movement, water changes, starting GH, starting pH etc will all affect a shell's dissolution rate and the resulting GH/KH changes. Fortunately, calcium is not toxic, so a little "overdosing" shouldn't harm anything.

I love the fact that one inexpensive little shell took care of my 5 gal so nicely.


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## ronnie (Feb 26, 2021)

From AAP the original manufacturer of Wonder Shells:

“Purchasers from AAP get correct instructions which would not be 3 small shells for a 5 gallon aquarium (this is MORE than a full dose), especially a planted aquarium, nor placing in a high water movement area.
6 small is approximately equal to one medium.”

The representative also mentioned that it is a passed down family business. And that the current owners are selling to any buyer. Because of this, if your purchase isn’t from AAP directly, we shouldn’t trust the dosing information on the packages. With a purchase from AAP, you get the original dosing formula.

They also provided links for me to look at, which I intend to.

Link 1:Wonder Shell Aquarium Mineral Blocks - AAP | Disease Preventative

link 2:Frequently Asked Questions | Aquarium & Pond | Fish | FAQ

link 3:Aquarium Chemistry | Calcium & KH & GH & pH & Electrolytes (ions)


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## PlantFan (Jun 19, 2021)

I have a container of Calcium Carbonate dust that I bought from a homebrew store. I have tried several times to dissolve it in RO water. The first time I just tried to dissolve it. The second time I tried to dissolve it while injecting CO2 to lower the pH. The third time I tried to dissolve a tiny 16.7 mg/l amount of it. This stuff (CaCO3) will not dissolve even if you beg and plead with it. So much for prepping your RO water with it. I thought it would be a good way to reduce sulfate because otherwise you're using CaSO4 to remineralize RO water. The thing about Calcium Carbonate, I have found, is that it releases its Calcium over time as it buffers your water. I recently put about a pound of chalky Seiryu pebbles in my overhead sump for a week and the GH increased 14 ppm probably because I inject CO2. The CaCO3 does dissolve. It just takes some acid and more time to do it. My thing is that I would like to be able to dissolve a known amount of it in a more controlled way. I would like to be able to dose it. I have a fourth experiment planned to dissolve chalk dust which will probably also fail. That is to use about 2 ml muriatic acid in five gallons of RO water to dissolve 16.7 mg/l CaCO3 over the course of three days. 16.7 mg/l CaCO3 is supposed to be the most that can be dissolved. But I have also seen 46 mg/l. I guess it just depends on how much acid is present. It dissolves better in colder water.

EDIT: LOL, Wonder Shells. Sorry I thought they were real shells. Disregard my dissertation. The Wonder Shells do seem to behave similarly to other Calcium Carbonates though. Interesting how the KH doesn't increase.


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## mistergreen (Mar 3, 2007)

PlantFan said:


> I have a container of Calcium Carbonate dust that I bought from a homebrew store. I have tried several times to dissolve it in RO water. The first time I just tried to dissolve it. The second time I tried to dissolve it while injecting CO2 to lower the pH. The third time I tried to dissolve a tiny 16.7 mg/l amount of it. This stuff (CaCO3) will not dissolve even if you beg and plead with it. So much for prepping your RO water with it. I thought it would be a good way to reduce sulfate because otherwise you're using CaSO4 to remineralize RO water. The thing about Calcium Carbonate, I have found, is that it releases its Calcium over time as it buffers your water. I recently put about a pound of chalky Seiryu pebbles in my overhead sump for a week and the GH increased 14 ppm probably because I inject CO2. The CaCO3 does dissolve. It just takes some acid and more time to do it. My thing is that I would like to be able to dissolve a known amount of it in a more controlled way. I would like to be able to dose it. I have a fourth experiment planned to dissolve chalk dust which will probably also fail. That is to use about 2 ml muriatic acid in five gallons of RO water to dissolve 16.7 mg/l CaCO3 over the course of three days. 16.7 mg/l CaCO3 is supposed to be most that can be dissolved. But I have also seen 46 mg/l. I guess it just depends on how much acid is present. It dissolves better in colder water.


Mother Nature dissolves limestone with rainwater that collects CO2 as it falls.

Your muriatic idea will work But make sure there is none of the acid left to harm livestock. I’ve forgotten how that’s done. 

found it.


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## johnwesley0 (Feb 23, 2021)

ronnie said:


> From AAP the original manufacturer of Wonder Shells:
> 
> “Purchasers from AAP get correct instructions which would not be 3 small shells for a 5 gallon aquarium (this is MORE than a full dose), especially a planted aquarium, nor placing in a high water movement area.
> 6 small is approximately equal to one medium.”
> ...



This news makes me nervous because none of the sellers on Amazon so much as mention the letters AAP on any of their packaging.


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## dwalstad (Apr 14, 2006)

I got mine from Pet Products, $1.87 for a package of 3 small shells. I don't know why other new sellers would bother to change a formula that seems to work well. It's not like calcium carbonate and sodium bisulfate are expensive ingredients. Here's link for where I got mine. PetProducts.com | The online store for everything pet.


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## jatcar95 (Oct 30, 2019)

I also found this strange when purchasing. I got mine through AAP (Wonder Shell Aquarium Mineral Blocks - AAP | Disease Preventative) (note: this page is for medicated and regular, this discussion is only about the regular). They claim to be the "ONLY Professional sellers" of Wonder Shells, and that other sellers are selling stale products that won't have full benefits. The part that "expires" seems to have to do with redox balancing and cation exchange and some other chemistry I don't understand....in other words, the products from other sellers should still increase hardness, as we've seen from this thread. I don't know what benefits the other science-y claims give, but for the purpose that we need them to serve, it seems unnecessary.

That being said, I guess there's something to say for supporting the original sellers, and you'll be getting a "fresher" product, allegedly.


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## johnwesley0 (Feb 23, 2021)

jatcar95 said:


> I also found this strange when purchasing. I got mine through AAP (Wonder Shell Aquarium Mineral Blocks - AAP | Disease Preventative) (note: this page is for medicated and regular, this discussion is only about the regular). They claim to be the "ONLY Professional sellers" of Wonder Shells, and that other sellers are selling stale products that won't have full benefits. The part that "expires" seems to have to do with redox balancing and cation exchange and some other chemistry I don't understand....in other words, the products from other sellers should still increase hardness, as we've seen from this thread. I don't know what benefits the other science-y claims give, but for the purpose that we need them to serve, it seems unnecessary.
> 
> That being said, I guess there's something to say for supporting the original sellers, and you'll be getting a "fresher" product, allegedly.


I feel better. Weco is one of the sellers on Amazon.


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## dwalstad (Apr 14, 2006)

jatcar95 said:


> I also found this strange when purchasing. I got mine through AAP (Wonder Shell Aquarium Mineral Blocks - AAP | Disease Preventative) (note: this page is for medicated and regular, this discussion is only about the regular). They claim to be the "ONLY Professional sellers" of Wonder Shells, and that other sellers are selling stale products that won't have full benefits. The part that "expires" seems to have to do with redox balancing and cation exchange and some other chemistry I don't understand....in other words, the products from other sellers should still increase hardness, as we've seen from this thread. I don't know what benefits the other science-y claims give, but for the purpose that we need them to serve, it seems unnecessary.
> 
> That being said, I guess there's something to say for supporting the original sellers, and you'll be getting a "fresher" product, allegedly.


You've made a good point. I'll probably buy future ones from AAP. Thanks!


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## johnwesley0 (Feb 23, 2021)

dwalstad said:


> For those living in NYC, Seattle, Raleigh, etc where water is ultra soft (GH = 0-2), Wonder Shells may be an easy and fast way to increase water hardness. Not only that, but the shells reportedly contain other nutrients associated with hardwater (Mg, K, S, B, etc). This is a bonanza for plants. Others on this forum have seen increased plant growth and I’m not surprised.
> 
> Even though my water is moderately hard this time of year, I went ahead with a little study.
> 
> ...


Yes! That was my experience, too. I only used one tiny-sized shell for about seven gallons of water: GH doubled from 5 drops to 10 over the space of six days (sorry, I can't be more precise because I was gone for most o that time.) No real effect on KH or PH. 

The shell is about half its original size after less than a week of moderate aeration from an air stone.


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## PlantFan (Jun 19, 2021)

This is a carefully compounded product.. I looked up the ingredients in Wonder Shells thinking they must contain Calcium Sulfate to better dissolve. A little surprisingly to me, they contain Calcium Carbonate which I have been unable to dissolve in a controlled way. They're probably adding an acid yet the pH does not change. It must be just the right amount of acid to react with the CO3. They have it balanced pretty well.


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## dwalstad (Apr 14, 2006)

PlantFan said:


> This is a carefully compounded product.. I looked up the ingredients in Wonder Shells thinking they must contain Calcium Sulfate to better dissolve. A little surprising to me, they contain Calcium Carbonate which I have been unable to dissolve in a controlled way. They're probably adding an acid yet the pH does not change. It must be just the right amount of acid to react with the CO3. They have it balanced pretty well.


I agree! Slick stuff. 

In another recent APC thread ('Fish Tank Water Quality'), Ronnie provided more information:

_Wonder Shells will generally not affect KH or pH. I remember reading that on the website. They claim to be made of Calcium Carbonate/CaCO3+ cations. 

“A few other elements found in minor & trace amounts include: Magnesium, Chloride, Sodium, Sulfate, Potassium, Bicarbonate, Bromide, Borate, Strontium, Fluoride (there is NO sodium thiosulfate despite poor search result claims).”
- Taken from Wonder Shell Aquarium Mineral Blocks - AAP | Disease Preventative_

Summary: I (Diana) speculated that Wonder Shells contain sodium bisulfate (an acidic salt) to dissolve the calcium carbonate faster. The acidity also keeps water pH from going up. [There's a possibility you might need to add a little NaHCO3. Best to check the GH and KH. Only if KH and pH is really low would I add NaHCO3 (i.e, via pure Baking Soda)].

The 'Fish Tank Water Quality' thread provides a little more background as to why a lot of us are enthusiastic about Wonder Shells.


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## mistergreen (Mar 3, 2007)

Yeah, I was thinking it’s a lot like baking powder in function. It’s a base and acid in one product That doesn’t get activated unless water is introduced. It uses something like corn starch in the mixture to delay any reactions.


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## dwalstad (Apr 14, 2006)

Wonderful explanation. The chemistry of aquarium keeping and baking come together! In first stage of baking (when you put dough into the oven), heat and moisture releases tiny CO2 gas bubbles from the dissolution of Baking Powder's CaCO3. These little CO2 bubbles make bread rise. The basic principle--dissolving CaCO3 with an acid--is the same as for the Wonder Shells.


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