I believe you are refering to one of my posts. It is glass for the 450 sf and I havn't seen it yet. I am just figuring for the most it may take. The fellow actually was trying to do it him self and called me to ask where to buy sand for his rented pot. The stuff he had was cloging the pot. I need the experienc as well as some cash so I kept the price pretty low. I'll take the five or six hundred for now. I did in fact just use soda to remove a coating and stain from a bridge on the pa turn pike. It used about 120 lbs over the 260 s.f.. I infact asked for $3.5 per s .f. and they could not have been more pleased with the out come. I also used soda, only a couple hundred lbs, on tuesday for a lightly painted brick wall and again a very happy customer. I know the soda only pots are much better but I'm not sure you get 300 s.f. of heavy paint off of brick with just 50 lbs? What kind of job do you get that kind of coverage from? Soda isn't as quick as glass and I have done as little as ten s.f. with 50 lbs on painted block. Any body else getting hundreds of s.f. of paint removal with a bag or two.