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gt turbo 11-22-2012 03:17 PM

Clay question
1 Attachment(s)
Ok guys, in barbados we have hand made pottery from red clay.

Just like what this guy is displaying.
Attachment 57608

Now here is my question, could I take this type of clay and grind it down to make a substrate additive assuming that it would have a similar cation exchange rate.

If this is possible this could be epic cause i can get the broken pot for free. So i'll be doing 1/2 inch of dirt with osmocote 14-14-14, then this clay and then capping with normal aquarium gravel.

Views, warnings and advice are very welcomed here.

GeoJB 11-22-2012 04:18 PM

I wonder too.

AirstoND 11-22-2012 04:33 PM

1) I would get it analyzed for elements that might be toxic in tank such as Cu(there's a water kit), it's just good practice depending on what you'll be keeping in tank. Just experiment a bit, if your shrimp and snails start dying, it could be the cause (I've actually had this happen to me but I suspect it was from using too many root tabs)

2) How big is your tank? I would use thin, say 1/8", slabs or pellets of it as your "bottom" substrate followed some finer grain, and finally a coarser river gravel or sand, 1:1:2 ratio of clay, fine sand, and coarse river gravel or sand.

3) The clay is also good for nitrogen reducing/fixing bacteria.

DogFish 11-22-2012 04:49 PM

I would just ask to see the bag the Red Clay came from to make the pots. Typically Powdered Red clay comes in 40# bags for about $20 in the States. This is pure 100% clay.

Most hobby store clays have polymers in them so they can be bake in a home oven or air dried. Those are much more expensive.

If he does have a 40# bag you can see to read the label, offer him $5 bucks for a 2 pounds of the powdered clay. You'll be way happier working with powdered clay than smashing up clay pots.

BTW - For what it would cost to analyzed a sample you could UPS a 40# bag to your home.

gt turbo 11-27-2012 02:29 PM

Ok guys, I called my "supplier" and asked some questions and I got some answers.

First off, remember guys I live in Barbados (the country not a place in the US) and we naturally have clay occurring, therefore it's not bagged or aything. We dig it up and make it into the pots and other craft. Now the stuff that i got for free, the only additives were water and heat, so it's about as natural as you can get.

They have done lots of testing and it's completely inert and non-toxic, the lady said i could eat it. lolololol :icon_lol: Plus you can eat off of it.

I'm currently testing it in what was my krib breeding tank with three Amazon swords. I potted them on Sunday and saw new leaves by monday. I'm monitoring the situation.

lochaber 11-28-2012 02:11 AM

I believe Barbados is a carbonate platform environment?

I'm really rusty on my geology, but the clay may have some carbonates in it, and may give your hardness and pH a bump (not necessarily). If you are using it as part of a dirted tank, or under a cap, it should be less noticeable.

heres something I ran across with a listing for composition of barbados clays (hopefully the link works...):

Those samples have very little carbonates or salts, so odds are it won't do much to pH or hardness.

So, yeah, if you can get some failed pottery, throw it in a sack, smash it up to gravel size or smaller, and give it a try. Let us know how it works out.

rrastro 11-28-2012 02:32 AM

rinse it well to avoid fine particulate in your water.

gt turbo 11-28-2012 05:57 PM

Thanks guys for the info and advice. I think we've settled on the concept that the clay is safe for use. So the question is, how to use it.

1 - Mixed in to the soil base.
2 - Placed as a layer on the soil base
3 - Mixed into the capping medium.
4 - Used as the capping medium
5 - A mix of 1, 2 & 3.

As per usual, I welcome your advice, please accompany it with some good reasoning.

wkndracer 11-28-2012 06:12 PM

What would be best for the plant uptake (imo) would be to use the raw (unfired) powder and mix it into the soil substrate then cap it.

AaronT 11-28-2012 06:17 PM

Get it into a fine powder and mix it into the soil. It will bind with the soil particles and make the nutrients available to the plant's roots.

Diana 11-28-2012 08:08 PM

Use the raw, unfired product, as it is dug out, and mix it with the lower layer, not the cap. Probably do not need much, either. Look into Mineralized Top Soil for the actual recipe.

This question has come up before, and the consensus was do not bother using broken pots. Once the clay is fired it may not have the same (useful) properties.

DogFish 11-29-2012 06:21 PM


Originally Posted by gt turbo (Post 2092091)
Thanks guys for the info and advice. I think we've settled on the concept that the clay is safe for use. So the question is, how to use it.

1 - Mixed in to the soil base.


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