so if I understood correctly you suggest getting hold of a piece of zinc and putting it in the system...

regarding the ratio would you suggest that even with my pump, a car radiator and only one block in the loop I could encounter significant drop in efficiency?

Anyway please be patient because I will be posting pictures very soon of my rig. I just need to understand what fittings to use to adapt tygon 8mm to the intake/outake of the car radiator.