# Hand Built Ceramic Caves



## whalebite (Jan 11, 2017)

A few years ago I made some ceramic rocks for my cichlids out of a terra cotta clay (what they make pots out of) They have done well with my fish, the semi-porous surface allows for more bacteria to colonize it (they have no glaze on them). I recently took a ceramics class and made some stoneware cichlid stones. They are high fire, and also have no glaze, as the glass surface is probably not as easy for bacteria to colonize, and the rough stoneware has a natural rock feel that is lost to a glaze. Glazing only creates a barrier around any ceramic piece as glazing the bottom will cause it to stick to the Cordierite shelf (which I think is safe), I have had a very old ceramic tiki house that appears to have been made for candles, the part that touches the gravel is unglazed (that has been in tanks for 10 years). However, I found out the make up them
Kaolin (clay) 25-65% 
Crystaline Silica - quartz 10-25% 
Silicon dioxide <5% 
Feldspar <2% 
Brown Iron Oxide <2% 
Titanium Dioxide <2% 
Kyanite <2% 
Pyrite <2%
The Pyrite is what concerns me, as it breaks down into sulfuric acid, it will lower the pH and free up the hard metals in the water.
I have had them soaking for a few weeks now, but the pH is yet to drop.


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## whalebite (Jan 11, 2017)

I have only been told that porous is good for bacteria, and it made sense, the more surface area the more bacteria (but yes, I agree oxygen is more important), but as I said that was only part of why I didn't glaze them, I mainly did it for visual reasons, as I am trying for a more natural look. My main question is the safety of the components in the stoneware, and how long will it take for most of the pyrite to become HCl?


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## Aaron S (Apr 4, 2015)

I wouldn't be concerned about the pyrite changing the pH of your tank for a lot of reasons. What I will suggest is the only way it has a chance to be harmful is if it all just instantly turns to acid in the water so take the pieces you want to put in the aquarium and place them in a bucket for a week before hand to make sure any fast reactions are done then move them over to the tank.


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## tanker3 (May 18, 2015)

When pyrite is immersed in water breaks down rapidly into iron oxides and sulfate. With only 2%, not sure how this will effect the water/fishes---it is a very small amount. I would just seal it to be safe.


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## whalebite (Jan 11, 2017)

Yeah I have had them lying in a bucket for at least a week, no change in pH, will probably leave them in for one more.


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