(newbie). Coal! Can It Be Used?

[apac]

Can 'hard coal' be used inside tanks in large amounts to create rocks and caves. keeping in mind this is for a high Ph african cichlid tank.
anyone out there have any experience with?

how would you clean it/prepare it, would it change the bio/chemical balance in the water if used in large amounts, would it catch the light or look dull?

there is an abundance of this in my part of the world, dug from deep down,- 'hard coal'. it would be a lot cheaper than using other types of black rock and it is comparitively light to other rock substances and is not as sharp as slate.
cheers,
Andrew.

 

[GrantyBoy]

I have never heard of anyone using coal in the aquarium. Always be dubious about using rock from the 'outside' world in a tank as you don't know what pesticides or other contaminates it could leak into the tank.

There is a good thread on here in the FAQ about rocks in the aquarium

 

[Majjie]

I'd be wary of using it - but a proper chemist might come along and be able to answer you better .

The coal itself isn't a problem - it's just carbon - but doesn't coal get deposited with toxic materials like sulphur and mercury. That's why coal smoke is not just bad for the environment (acid rain/CO2 etc) but is also toxic.

I guess if you left it to soak for a long time then anything soluble would be leached out - but I'm not sure I'd risk it.

 

[apac]

the reason it has come into my head is that i have heard of it being used, but maybe not in large amounts. Anthrasite - 'hard coal' is the purist of coals i believe. i wonder if there is a safe way to 'leach' it as you say. any aquarium chemists out there??

 

[zoekin8yg]

I would say no, its likely to make the water acidic by making carbonic acid. But then again you do use activated carbon in filters (or at least can) (If my brain was working I would be able to give a better answer). Im sure someone has a better answer

 

[raptorrex]

NO! tar, arsenic, sulphur, to name a few

 

[apac]

i think thats a no then! pity.

 

[gpgscott]

NO! tar, arsenic, sulphur, to name a few

Activated carbon comes from many sources only one of which is coal. It is processed using extreme heat and then is is cleaned of impurities with either acids or steam. There are many different types of ac depending on the goal. For aquarium use you want a uniformly graded product with what is called a 'macroporous' structure to trap dissolved organic waste. The qouted poster is quite correct, not suitable for the aquarium. Scott

 

[fiki]

don't do it. the carbon stays in your filter for a reason.

More carbon means that carbonate may form. Carbonate reaction with water = a change in pH. I think the water would become more basic? Not sure. But don't do it. Also, the coal may break off once in a while, and the small particles may get into the fish's gills and cause issues.

Just - stay away from it...

 

[loachman]

don't do it. the carbon stays in your filter for a reason.

More carbon means that carbonate may form. Carbonate reaction with water = a change in pH. I think the water would become more basic? Not sure. But don't do it. Also, the coal may break off once in a while, and the small particles may get into the fish's gills and cause issues.

Just - stay away from it...

For that to happen, you'd need

C(coal) + O2 -> CO2

CO2+H2O -> H2CO3 (acid)

Assuming it happens, carbonic acid (H2CO3) makes the water more acidic or lowers pH.

The first reaction doesn't realistically happen though. Not at the conditions found in an aquarium. It's what happens when you burn coal.

The main reason that you don't want to do it is that coal is dirty. It's got potentially nasty impurities (mercury, arsenic, lead), will probably disintegrate, etc.

 

[Majjie]

I mentioned this to a scientist friend of mine who didn't think there'd be much problem. He reckons that the toxins come from burning the coal - and you're not going to be doing that in your tank. He suggested trying the usual vinegar test (for carbonate impurities), soaking it in water for a couple of weeks and then going ahead. Anthracite is 95% carbon - not the same as simple carbonates.

Mind you - he's not really a chemist (although he lectures in basic chemistry) and he doesn't really like African cichlids ............

If there were impurities in the coal you could always get problems if the coal broke up in the tank. It's the sulphur, in coal deposits, that causes acidic run off from coal mines - in the form of sulphuric acid - not what you'd want in an African cichlid tank

 

[apac]

i've read environmental articles on the web and how old abandoned mines with contaminated water build ups have ended up in rivers turning the water really acidic, but i thought this was to do with the mining process and trace metals etc being left behind in the mine itself, but as mentioned sulphur would not be good!!. i think there is definitely a concern with the coal softening the water. i've posted some questions around the web on geology and chemistry forums to see if there is any expertise available on this matter (no replies as yet). i have spoken to a member of another fish forum who has used it without problem in a African cichlid Mbuna set-up. and as stated in above posts it is the burning process that gives off the toxins.
it would be a risky business using it if you are unsure. it's just an idea that popped into my head as i plan on setting up a tank soon. if it was safe to use then it could make for a really interesting constructed shelf background and ideal for stacking as rocks. its not expensive, its relatively light weight, its not as sharp as slate, and it is black n shiny and would reflect nicely off aquarium lighting and also be a great dark backing for the fish to stand out against. the only draw back to using it is that i've heard that is a bugger to clean before putting in a tank!

 

[Majjie]

I bet it would look stunning It's just that doubt about any contaminants

 

[apac]

i think the overall feeling is it would be a bad idea.
instead, any one know where i can get black obsidian glass rock? there are very few volcanos in cardiff! lol.

 

[andywg]

According ot a post from nmonks in an earlier thread it would appear that coal is perfectly fine to use in the aquarium.