from everything I've been able to find, it *is* banned in Canada.. that is, it used to be sold for canning but now *isn't* available, because it has been determined that calcium citrate is sufficient.
You can maybe find packets of pickle crisp (which some might assume is the C.H. but no-- it is calcium citrate.)
There are as well, some chemical companies in Alberta and B.C.that sell it, but in 25 kg. bags x "a lot". And the suggestion that it be bought from a lab supply source won't work either because they won't sell to individuals. Moreless has had a hard time believing it's not available in Canada, but that's because he lives in the U.S. where it is, and he hasn't dealt with things here.
Most people who look for it Canada are "reef enthusiasts" usually, and they find they have to get it from the U.S. (and/or perhaps in large quantities.)
I finally bought some from an aquarium person on ebay, and he tells me he has shipped to Canada before...I am simply hoping it makes it here, and doesn't get held up and/or waylaid in Customs.
That was the only form of the stuff I felt comfortable with. I note that they sell plain "lime" for lawns and "dog runs", at home depot, I believe, and a few other places, but I'm not comfortable with that...though it may be fine--the reef stuff is used to support very delicate coral systems and fish, so it feels better to me.
so, I bought a pound for 5.00 and the shipping on it is (hold your breath) 17.00 + 2.00 insurance.
I figure it's worth it if it works as well as I hear.
If you are interested, just key in Calcium hydroxide on ebay. The person also has four lb. bags that ship for 22.00.
Sorry, don't have the link here...
will post when it arrives...it has to wait till the 28th to ship.