View Single Post
  #4   Report Post  
Old 08-11-2010, 07:13 PM posted to rec.gardens
zxcvbob zxcvbob is offline
external usenet poster
 
First recorded activity by GardenBanter: Jul 2006
Posts: 535
Default Calcium Sulfate / Gypsum

mj wrote:
On Nov 8, 1:55 pm, zxcvbob wrote:
mj wrote:
Where can I buy a pound or two of this and not have the shipping be
crazy? Where could I buy it in say a local store? I have all the other
chemicals for my hydroponics except this one and I don't want to have
to buy a ton.
MJ

Plaster of Paris. You'll probably have to hydrate it to make it useful.

Bob


As in every elementary school project plaster of Paris? I need it in
a dry form mixed with all the other stuff and then it is dissolved
into the water system.



Yes. But you want hydrated calcium sulfate, CaSO4·2(H20), and Plaster
of Paris has been dehydrated to 2(CaSO4)·H2O. So you'll probably want
to add excess water, let it harden, then pulverize it.

Bob