I can't answer your question about the liquid versus the powder.
Uny Edit: strike through the Mountain Rose recommendation. Some of the past posts/links DO show me recommending Mountain Rose as a source, until I found out this: http://curezone.com/forums/fm.asp?i=1667343
As for a good source to purchase bentonite clay...
Mountain Rose Herbs
http://www.mountainroseherbs.com/clay/clay.html
Hence this is the source I know recommend for 'food grade' bentonite clay: http://www.theholistichorse.com/Detox.shtml
Water, do NOT feel badly about that - no one can possibly read every post made on this forum (and even if someone could, that someone couldn't possibly remember everything in every post!).
Blessings,
Uny