# the deal with calcium bentonite



## Rain_Frog (Apr 27, 2004)

Okay, for those experimenting with Calcium bentonite, can you explain how you use it for backgrounds?

And, I heard somewhere over the water that sodium bentonite (stuff people are using for clay substrate) can be harmful to animals in the long run because of high aluminum content-- I think I read that information in a garden pond book.

Does it need to go through any curing process like flevopol / epoxy/ great stuff, etc? Can it be used for semi-aquatic anuran setups?


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## Julio (Oct 8, 2007)

well i hope Ed can shine a light on this, i saw one of his tank setups with calcium bentonite that had great growth on it, but he can give you more details on it.


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## Corpus Callosum (Apr 7, 2007)

Might want to grab some and experiment as well.. I haven't messed around with it enough to offer any tips, but it's my new best friend.


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## Rain_Frog (Apr 27, 2004)

If it's used for koi ponds, I'm also wondering if it could be used in aquatic frog tanks for a background, since aquatic frogs can injure themselves on sharp / rough decorations.


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## markbudde (Jan 4, 2008)

Ed can probably offer better advice than anyone else. I have recently used some to seal off some gaps in my viv and have been happy so far with the results. I mixed peat and bentonite and it looks very nice and seems like it will hold up (and hold shape) very well. Initially I tried using bentonite alone and it seemed like it would dissolve/erode very quickly. I used a kitty litter which said 100% natural, no scents added. I think it must be calcium bentonite, not sodium bentonite because sodium bentonite supposedly expands 3 times in water, and the kitty litter did not expand. I'll post pics later, but it looks very nice and the frogs don't seem to mine standing on it.
-mark


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## Ed (Sep 19, 2004)

Rain_Frog said:


> Okay, for those experimenting with Calcium bentonite, can you explain how you use it for backgrounds?
> 
> And, I heard somewhere over the water that sodium bentonite (stuff people are using for clay substrate) can be harmful to animals in the long run because of high aluminum content-- I think I read that information in a garden pond book.
> 
> Does it need to go through any curing process like flevopol / epoxy/ great stuff, etc? Can it be used for semi-aquatic anuran setups?


I have some significant doubts as to the bentonite being the source of the aluminum ion... while bentonite does contain almuminum, the ion is not able to come free from the particle as it is actually part of the actual molecule and is not interchangable. 
If there is actual hard proof (necropsy with appropriate assays) then the aluminum probably was either a contaminant or from an alternate source. All because a material contains an ion it does not mean that the ion is available or free to the enviroment. 
I did a search on alumina toxicity bentonite on google scholar and was unable to find anything that supports the idea that it releases aluminum ions... 

If you are using it submerged you might have better sucess using sodium bentonite or sodium exchanged calcium bentonite as these swell more and have a greater stability when used as a pond lining. 

Ed


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## zBrinks (Jul 16, 2006)

I'll be starting on a 6'x2'x3' plywood viv for Theloderma corticale soon, and was considering using this for the background. Any idea if it holds up under running water(ie waterfall, not just dripwall)? Do you just mix it with peat, water, slap it on, and let it dry?


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## Rain_Frog (Apr 27, 2004)

Ed, any specific reason why you are recommending calcium bentonite over sodium bentonite for backgrounds?


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## capitale (Nov 7, 2008)

Rain_Frog said:


> And, I heard somewhere over the water that sodium bentonite (stuff people are using for clay substrate) can be harmful to animals in the long run because of high aluminum content-- I think I read that information in a garden pond book.


I'm with Ed on this -the toxic aluminum levels wouldn't be due to the bentonite. Although I have read that many tropical soils (that are composed mostly of clay) have toxic levels of aluminum. 

Just speculation here, but I would guess some bentonite suppliers aren't refining their product (ie calcium bentonite intended for construction material) and could contain potentially toxic amounts of aluminum.


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## Ed (Sep 19, 2004)

On a little further digging into the literature.. toxicity of aluminum appears to be significantly reduced by humic acids. In the enclosures under discussion, there should be significant levels of humates from leaf litter, peat moss, sphagnum moss and/or cocohusk materials used in the creation of the substrates/drip walls. 
IF the pH was below 5.5 in the pond (which is usually not a good thing to begin with for many commonly kept ornamental pond fish) and there weren't any humic acids available to complex the aluminum ions in solution, and the ions stayed suspended and didn't precipitate out as aluminum hydroxide or aluminum phosphate (both of which are insoluable) then there may have been toxicity issues. 

Depending on the tropical type soil or clay source used in the presence of an acidic pH (although the literature appears to point to one below 5.5) there maybe sufficient aluminum ions to be toxic to plants.. (and potentially animals) but the testing on this may have been biased due to other ions present in the solutions (such as chloride, sulphate or nitrate) as strong acids were used to get the pH low enough. Many plants (especially tropicals) have defences against aluminum toxicity and as I noted above, complexing with humic acids can reduce toxicity. In addition, the pH really needs to be below 5.5.... 

Ed


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## Ed (Sep 19, 2004)

Rain_Frog said:


> Ed, any specific reason why you are recommending calcium bentonite over sodium bentonite for backgrounds?


Because I haven't worked with sodium bentonite as of yet... If I had worked with it, then I would be comfortable giving it a recommendation but since I don't have any experience with it.... 

Ed


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## Ed (Sep 19, 2004)

zBrinks said:


> I'll be starting on a 6'x2'x3' plywood viv for Theloderma corticale soon, and was considering using this for the background. Any idea if it holds up under running water(ie waterfall, not just dripwall)? Do you just mix it with peat, water, slap it on, and let it dry?


If you let it dry until it cracks then it won't be stable at all. It will depend on how strong of a current you intend to try with it. 
Once moss began to grow it, I was able to increase the drip wall until very small but continous streams ran down the wall without it destabailizing but that drip wall is also interspersed with some rock shelfs as well as some tree fern strips to encourage plant growth so all of the clay is simply not trying to support itself. 

You need to let it dry until it begins to set. Once it sets it will hold up to some water flow. 

Ed


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## zBrinks (Jul 16, 2006)

Thanks Ed.

I think I'll figure out a way to add support to it, if I go this route. I may just try it in certain areas, with the primary hardscape concrete rockwork.


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## Rain_Frog (Apr 27, 2004)

Ed,

What kind of curing process is involved? Can I add it to an existing tank, or do I have to scrap the enclosure / or add it to a new, unused tank like our other DIY methods?


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## Ed (Sep 19, 2004)

Letting it air dry and set. There is a fine line between too much drying (when it shows cracks) and just right. 

I'm not sure I would use the calcium bentonite in an aquatic setup as there is the risk the pH being high. 

Ed


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## asilsdorf (Sep 7, 2005)

I understand that clay kitty litter is bentonite clay. I have some kitty litter and the package reads. Ingredient: ground clay

I was wondering if it was sodium bentonite or calcium bentonite so I put some in vinegar and it fizzed. Does this mean I have calcium bentonite? or is it impossible to tell since the package just reads ground clay?

Opinions?


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## Rain_Frog (Apr 27, 2004)

snip: Letting it air dry and set. There is a fine line between too much drying (when it shows cracks) and just right. 

I'm not sure I would use the calcium bentonite in an aquatic setup as there is the risk the pH being high. /endsnip

For clarification, my last question was about terrestrial / vivarium setups.

Can I "air dry and set" in an existing vivarium (after taking out the frogs for a few days)? My main question was if there was a curing process that is toxic to frogs until it's it's finished "air drying and setting." We don't add great stuff or silicone to an existing vivarium, we add it before we add plants / dirt/ etc,


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## markbudde (Jan 4, 2008)

No, there is nothing special about the curing process, no chemical reactions or anything. I think the "curing" is really just allowing the water to completely get into the clay.


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## Ed (Sep 19, 2004)

asilsdorf said:


> I understand that clay kitty litter is bentonite clay. I have some kitty litter and the package reads. Ingredient: ground clay
> 
> I was wondering if it was sodium bentonite or calcium bentonite so I put some in vinegar and it fizzed. Does this mean I have calcium bentonite? or is it impossible to tell since the package just reads ground clay?
> 
> Opinions?


If you are getting fizzing, this doesn't mean that calcium is present. It means that carbonate is present. This could come from a lot of sources and doesnt' indicate which type of clay was used for your kitty litter. Some litters are an admixture of clays with contaminents (which could be the source for your fizzyness). The clays added together are typically sodium and calcium bentonite. The reason is because the sodium bentonite swells which enables it to clump a little better. 

Ed


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## Ed (Sep 19, 2004)

Rain_Frog said:


> snip: Letting it air dry and set. There is a fine line between too much drying (when it shows cracks) and just right.
> 
> I'm not sure I would use the calcium bentonite in an aquatic setup as there is the risk the pH being high. /endsnip
> 
> ...


If you pull the frogs out you can sculpt it into place (I'm not using pure bentonite in any areas where the frogs have access. I've always mixed it with some form of organics (peat, coco husk, long fiber sphagnum moss, ground long fiber sphagnum moss, cypress mulch fines or a mixture of those items) and let it set it should be fine. I did the background in the one thread when the tank was on its back. 

Ed


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## Rain_Frog (Apr 27, 2004)

what brand of kitty litter are people using? Anyone know of a good source to purchase calcium bentonite if i cannot find a decent type of litter at the petstore?


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## NathanB (Jan 21, 2008)

Is there more info on this as a background anywhere?


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## Ed (Sep 19, 2004)

there are a number of threads discussing this. Try searching calcium bentonite. 

Ed


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## Corpus Callosum (Apr 7, 2007)

Doug, unless you know for a fact your brand of kitty litter has calcium bentonite in it, it could just be another bentonite or who knows what else. I would search for calcium bentonite in the koi pond industry, it is used as a pond liner.


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