Thanks so much for the info, I had no idea it was that slow to regenerate. I'm going out in search of a coir brick today.
George,
Coir is a byproduct of the coconut industry. It is the fine fibers that remain on the husks after the longer ones have been removed for coir rugs. Apparently there are mountainous supplies of it in Sri Lanka, just sitting around.
It has similar properties to sphagnum peat moss, its light, has greater water retention lasts longer, is in plentiful supply and is renewable.