Justin,
Look up Falcon Laboratories right there in your town. Give them a call and have their salesman, Brian Teachout, contact you. If he can't (because you are not a business), call him and explain what you need, and I can get the product you need.
I would suggest M.A.D. (Mild Acid Detergent) which is a 5% phosphoric acid mixture with some detergent added. Your problem is probably lime from the water, and M.A.D. will take care of it. Try some vinegar. If that works, M.A.D. is your answer.
If you just need a super heavy duty cleaner, call LeMaster's Janitor supply and get a gallon of Kleen-All. Kleen-All is what Simple Green is trying to be (except it's purple). I'm serious, once you have a gallon of Kleen-All around, you will buy it by the case. Cheap too, around $7/gal.
I'm not kidding, you can de-grease your car engine with it.