So, let me start off by saying that I want my water at a Ph of 6.8 and a GH of 2-4 (for fundulopanchax gardneri killifish). But I have a slight problem. I have well water with a Ph of 8.2 and a GH of 7-8. My theory was that if half of the water is RO, then my GH would be 4ish and my Ph would be somewhere around 7.8 (my guess). Obviously, I can't get my Ph below 7 by adding RO. So how could I keep my GH at four (by adding half RO), but get my Ph to 6.8? Originally I was thinking about putting in a piece of driftwood, but that wouldn't allow me to lower it to 6.8 exactly. How should I go about getting my water to that point? Really, the Ph could be in the range of 6.5 to 7, so it doesn't need to be exact. Should I try the driftwood? Thanks for any replies in advance.