[GRIMM]

Alright, so I made up a large batch of clay substrate about 3 weeks ago. I managed to bake about half of the batch, but then I didnt get around to firing the rest of it. I kept it covered with saran wrap. As you can see in the picture, the top layer is a relatively normal colour, however just below the surface it is dark, and smells like TOTAL SH*T!!! Is the rest of the clay ruined? Is this normal? Will the fired clay absorb water and get like this over time anyways?

I used about 3 parts redart, 1 part sodium bentonite (litter), 1 part calcium carbonate sand, 1 part peat moss, a small tub of dusting calcium, 1-2 table spoons of sugar and corn starch also.

Thanks for any help, and sorry if this has been mentioned in the +330 page clay substrate thread lol.

 

[Ed]

What you are smelling is anerobic bacterial growth... It is the result of poor air penetration due to lack of particle size of the clay. It will go away once you work the clay to get particles formed.

Ed

 

[GRIMM]

Thanks Ed. I'll hold my breath and mash up the next cubed batch for firing. Unreal soggy a$$ stench! I'll take it as an OK sign though since you know whats going on

 

[Mitch]

One you fire it everything on the clay will be killed so the stench will be gone.

 

[Okapi]

The bacteria was feeding on the sugar in anaerobic conditions

 

[GRIMM]

So, wont this start to happen again once inside the tank and under leaves? I understand there will be air gaps and microfauna flourishing down there, but I cant imagine there being much air circulation. I would rather not have a stink bomb of a tank in my living room.

Also, another question specifically for you Ed. Have you ever fired your clay at higher temperatures, or studied how it would effect the clay? I already posted this question in Pumilo's thread, but never got an concrete reply. I was thinking of firing it at roughly 900-1000 degrees fahrenheit. At this point, the clay will retain it's shape for an extended period of time, but it will not be converted into a ceramic. I realize that most of the other componenets will be burnt and rendered useless, but the calcium carbonate will stay in tack. Im mostly worried about this clay becoming a big lump. It became soft much to fast for my liking during my moisture test run. I might end up mixing it with a bunch of charcoal anyways to help prevent large clumps from forming. Thanks for any info you can give me.

 

[Ed]

If you get the clay structure right, you are going to have air penetration into the substrate that is going to prevent this from occuring again. (also plant roots help keep this from happening).
I have not fired the clay as I have been threatend with death as we just got a new oven and the wife knows my tendency to experiment.. I do have good information on the firing process from Matt Mirabella, but I don't want to post it without his permission. If you want to shoot me a e-mail, I'll send you a copy of it.

Ed

 

[GRIMM]

Pm on it's way! Thanks.

 

[earthfrog]

It would seem this situation is totally preventable by using the kitty litter and mixing it up until fairly stiff in consistency---not fully saturated, so that air pockets may become trapped when mixing by hand---turning the clay much like you would bread dough to trap air inside. In this case, firing the clay would be fairly unnecessary with this method, I think...
Granted, it could stand to be amended with good fillers, but I've had no problem with stink this way.

 

[Pumilo]

That was my first thought, too. Anerobic bacterial growth. I've seen it in poorly set up reef tanks before.

 

[Ed]

It would seem this situation is totally preventable by using the kitty litter and mixing it up until fairly stiff in consistency---not fully saturated, so that air pockets may become trapped when mixing by hand---turning the clay much like you would bread dough to trap air inside. In this case, firing the clay would be fairly unnecessary with this method, I think...
Granted, it could stand to be amended with good fillers, but I've had no problem with stink this way.

Hi Susan,

working it to incorporate air is only going to prevent anaerobic growth for a short period of time, and only in those areas where there are bubbles of air trapped (again for a short period of time). Once the incorporated air is used by the bacteria, anaerobic growth would start. The reason this occurs is because simply working the clay doesn't mean that air can penetrate it any better than before.

Ed

 

[earthfrog]

Hi Susan,

working it to incorporate air is only going to prevent anaerobic growth for a short period of time, and only in those areas where there are bubbles of air trapped (again for a short period of time). Once the incorporated air is used by the bacteria, anaerobic growth would start. The reason this occurs is because simply working the clay doesn't mean that air can penetrate it any better than before.

Ed

Would this imbalance not be counteracted by other beneficials carried in plant roots, 'buggies' and other additives (unless they had been cleaned first)?

 

[GRIMM]

I think the main way to stop this from happening is by not letting it sit in a bucket for 3 weeks like me haha. Once you make the mixture, cube it up and bake it asap!

 

[Ed]

When I have broken down some clay substrate tanks that weren't fired, I haven't seen or smelled any anaerobic issues. I think in this case we had the problem as it was in a sealed bucket which is already a fairly stagnet situation for the clay.

Ed