[StirCrazy]

Tufa is formed when water evaporates from lime-rich waters, leaving calcite (calcium carbonate) to crystallize, often with impurities of iron oxides (rust), which give tufa its yellow and red coloration.

if you get tufa I would sugest you hand pick it and look for chunks that are white, this will help in minimizing the amount of iron oxides which can help fuel algae blooms.

I looked at Tufa as a money saving idea when I was first setting up my tank but I decided to spend the extra money and get live rock. my thinking was "while tufa might be perfectily fine, there is no guarente that it won;t have minerals that are undesiriable or unwanted. And if it did have thease I would hate to have to go through all the problems of tracking down the cause of a potential problem, then having to figure out how to deal with it."

here are some pictures of Tufa
http://www.tufa.bc.ca/gallery.htm


Water-worn limestone, limestone that is very attractive in appearance because of the action of water on its softer parts, is sometimes confused with tufa. It is a calcium carbonate, but it is not tufa, so check and see which it is.

here are a couple retailers in Calgary

EDWARDS GARDEN CENTER & LANDSCAPING (R)
Calgary, AB
403-288-9638

GARDEN CREATIONS (R)
Calgary, AB
403-236-5175


And one in St. Albert

HOLE'S GREENHOUSES & GARDENS LTD. (R)
St. Albert, AB
780-419-6800

hope this helps

Steve