Hello, my son and I are wanting to build a chamber! Thanks for this website! Which one of these would you recommend ? http://www.harborfreight.com/catalogsearch/result?q=vacuum+pump I plan on buying vacuum gauge, complete chamber plumbing kit, cactus juice, and universal lid from you. If I plan on using mason jar, would I need to purchase anything else? Thanks!

Either Harbor Freight pumps will be fine.  Save your money and go with the cheaper one.  Actually, I prefer a Robinair 15310 for an expensive vacuum pump.  Robinair has been in the vacuum pump business for a long time.  Sure this model is still made in China but at least it is made by a company that makes vacuum pumps rather than a company that sources cheap tools!  It sounds like you have all the necessary parts to get you up and running in short order!  Be sure to read my article "Vacuum Explanation" in the Help Center under the Cactus Juice Stabilizing Resources section.  It has a lot of information on vacuum and vacuum pumps.