Can coal be used in Lake Malawi set ups?

[Sye]

I am in the process of designing my Lake Malawi set up and have read previously that coal can be used to make caves.

Could someone please confirm this? If I can what are the procedures for cleaning it and making it safe?

Would it possibly make the water acidic as it contains sulphur which in turn would create sulphuric acid(if I remember correct from chemistry )

 

[gixer]

i have heard about this too...although i always though coal would soften water rather than raise hardness..

lthough malawi Is full of coal and anthracite..

 

[MRshouty]

wouldn't the coal make the water dirty?