re: greensand

Jeff and Denise,

Greensand, at least in the UK, is the name give to a number of marine
sediments, including some rich in phosphatic nodules (called coprolites -
but they are not!). These coprolites have been mined for centuries as
fertilizer. Incidentally, real coprolites are fossilized animal droppings.
The greensand is green because of a mineral called Glauconite, which is
formed in marine conditions of high nutrient levels. Phosphorus is an
important part of Glauconite.

Anyhow, the sand is calcareous and *will* harden the water.

If hard water isn't a problem, then the Greensand will probably be okay.
But you would be best to leave it out, and use silica (glass) sand, which
is inert.

All the best,



From  Neale Monks' Macintosh PowerBook, at...

Department of Palaeontology, Natural History Museum, London, SW7 5BD
Internet: N.Monks at nhm_ac.uk, Telephone: 0171-938-9007