hi ghost
i understand where you are coming from. the waterwetter is a concentrated solution that is meant to be used together with distilled water. my understanding is that even in motorcar, most of the wrkshop just use tap-water and pour in waterwetter. (that is what they did with my car too la haha) in this case, it is not recommended because tap-water have purities in it. that is why i have the intention to bring in the supercool waterwetter which is a premix solution that is ready to use. just flush out and pour in. slightly more expensive than the concentrated waterwetter but beats having the problem of a radiator failure right?
regards.