Generally most large grocery stores that have meat markets and anywhere that sells welding supplies can also get you dry ice. But How's this for service? [FONT=Arial, Times, serif]
R E Dry Ice[/FONT][FONT=Arial, Times, serif]
105 East 1/2 Hickory Street
[/FONT][FONT=Arial, Times, serif]Mankato, MN[/FONT][FONT=Arial, Times, serif]
(507) 386-1556 [/FONT]
It's been a while but someone posted a link a couple years back to the world Dry Ice Directory there are 5 other dealers "in your area" but only one in town.
Dry Ice Directory - Where to buy Dry Ice
Unfortunately, you can't search for "Dry Ice" in the CB search engine or you could have found that link.
As for the rest of the question. Remember that the whole cloud of
smoke depends on the water being very warm. However in a short amount of time the ice is going to cool the water down. Having the device keep putting out
smoke over 10 minutes is going to take some clever work on your part. If the container is too small the dry ice will freeze the water. If the container's too large it will blow through all the dry ice too fast. Good luck. I would look into renting a
tiny fogger if possible and do it with chemical
fog instead.