housebricks and celcon(sp?) blocks

I went out to get my weekly supply of daphnia the other day and a super tall 36"
50 gallon tank fell into my pocket. None of my rellys are getting any christmas
presents, and if this bath size is ever to get wet, it is going to have to be on
the cheap, hence the first of what will probably be many "is this stuff safe &
what probs" type post from me (set your kill-files now!).
First, I have (of course) read the krib archive about cheap bio-media, and was
interested to read that most people have opted for non-porous material like
chopped up drinking straws etc, surely the objective is to achieve the greatest
possible surface area/volume. Would not something like smashed up terra cotta
plant pots or other fired ceramic material do the trick more effectively? Would
the gradual release of fragments or dust be an insurmountable problem? I am
considering a home-made bio tower and sump, surely a layer of coarse filter wool
after the bio tower would solve the problems, your thoughts please.
As the tank is very tall, I shall need some terracing or something to use the
height. I thought I could use ordinary house bricks topped with perhaps perspex
or glass bordered with a log and in-filled with substrate  could give me a
second "storey".
Another idea for building in the tank is ordinary potter's clay, shaped into a
multi-layer grotto and fired in the oven, any thoughts or caveats?
I see I have rambled on long enough, your comments will be much appreciated.
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