Consider this stuff. Jim Sims recommended it and it seems to work really well.
http://www.refrig.com/nylog.html
Also, on the Procooler, they will replace it after you open it up a few times. I'm not sure if they make you send in your old one but the price was somewhere around $100 to 150, which isn't cheap but beats 299 for a new one. The support on the Procooler is unbeatable!