JPL-SoftTub

Yesterday, I purchased a 2 year-old used SoftTub 300. It is currently running since late last night and I obviously need to treat the water. I have been frantically reading all day, and quite frankly my eyes are about to buldge out of my head!!! It is so overwhelming with all the different chemicals and different procedures. Can someone please give me a quick run down of what I need to do. I called a SoftTub dealership and they told me that I MUST use only SoftTub chemicals. Is this true? or a sales pitch? probably the latter I imagine. Unfortunately I have no previous experience with balancing the water, so the simplest procedure would be greatly appreciated? Thanks...this site is so usefull and full of great advise!! Jason