For a little more than $100/gal., ColeParmer sells a silicone-based heat transfer fluid that pumps easier than water. The problem is that the $100 does not include the rubber free pump, the higher quality tubing, or the gloves you will have to wear to handle it. You are looking at food grade tubing sold in 50' lengths for about $100, pumps in the multi hundred range, and gloves that do not absorb silicone (a health hazarous substance).