Product Review: Thermo-Cure cooling system flush.

First time I flushed the heater core n our first 67model, I didn't use a flushing Tee. I simply took the 2 hoses off the engine a draped them over the fender. Garden hose in one heater hose until water ran clear. A coworker walked out there and said now reverse direction of flow. Yep, nasty water again. I let it run until it ran clear and reversed direction of flow again and got dirty water again. I repeated this procedure like half dozen times before I got clear water both ways. Best I could decipher, a heater core has places in it that a flushing Tee in one hose would never remove. Anyway she went from very little heat to run you out of the car heat.