mine says 6 which i have just goggled says its fine, i think im going to stick with killifish and rainbow fish to make it easier for me and i will get a pair of Bolivian ram when the ph drops.
There may be some misunderstanding here, I will hopefully explain it.
First, the GH of 6, what unit of measurement is this? The hobby uses two interchangeably, degrees (expressed as 6 dH) and ppm (parts per million, hich happens to be the same as mg/l) expressed as 6 ppm. To switch from one to the other you use 17.9 and multiply dH by 17.9 to get the equivalent ppm, or divide ppm by 17.9 to get the equivalent dH. These two un its are vastly different. For example, 6 ppm would be 107 ppm. But 6 ppm would be less than half of 1 dH.
The second thing to recognize is that different fish species have or can have very different requirements when it comes to GH, even more than pH. This is why we must know the actual GH number. There is no value in members recommending say livebearers if the GH is 6 ppm, or even 6 dH, as both are much too soft. But soft water species would thrive in either.
No reliable website can say a GH of 6 is "fine" unless they reference specific species. You mention some species. Killifish is a large group of small fish, many from soft water and I believe some are from moderately hard water (the killifish experts can help with this if specific species are mentioned). Rainbow fish is also a large grouping, and some of these need very soft water, while others need moderately hard. The Bolivian Ram is a soft water fish that may be able to tolerate moderately hard, but I wouldn't.
On the pH. This is closely connected to the GH and KH. Adjusting the pH depends upon the buffering capacity of the GH and KH, especially the latter. We/you need to know these numbers before you can make any decision. Adding organic matter can cause the pH to lower, but only depending upon the level of the GH and KH.
Adjusting water parameters is believe me an extremely complicated business.
