Well, the pH of my R.O./D.I. water is far below a 7. My pH test kit goes down as low as 6.0, and my R.O. water is no higher than that. Like you said, the TDS etc. is 0, but the pH is not a 7. So you're saying that having a GH of 1dGH and 1 dKH are acceptable parameters? If that's the case, then I can probably mix a gallon to a gallon and a half of tap to 3.5-4 gallons of R.O. The problem is, I was under the impression that I should be shooting for a KH of at least 4, and a GH of well, I don't know, 2-3? To get those results I need to mix more tap with my R.O., and when I do, my pH shoots up too high.
I understand that chemicals are not the 'answer,' but if my TDS is around 3-4 dKH/GH, wouldn't a pH down work much more effectively and be much safer in terms of stability (since there is less buffering capacity in the water)?
On a similar note, when I was buffering my water with additives, I was using Kent R.O. Right and Sodium BiCarbonate. The reason I abandoned this was that the Sodium BiCarbonate would raise my pH too high, and I recently read an article where someone claimed the same thing happened to them (implying that carbonate buffers raise the pH too high) and that this person switched to Seachem Alkaline Buffer. Has anyone used this product and had better luck at keeping a low pH while still adding some KH?