Originally Posted by dazeek
We contacted the water company today and they refered us to their website. I had already been on it but dont see kh/gh listed. I'm pasting a link, if anyone has time can you see if you can make sense of the info and what i'd need to do to lower my ph?
I've seen that site before, another PN member linked it. Anyway, they give hardness in the chart at mg/liter, and at the bottom they explain that mg/l is equivalent to ppm (parts per million) so that's easy. Your water is in the range of 71 to 206 ppm, which equates to soft to moderately hard. We use dGH for the hardness range in our fish profiles, and you can convert ppm to dGH by dividing by 17.8 or 17.9 (have trouble remembering). I also have a chart I check, and with 70-140 ppm being 4-8 dGH which is considered soft, and 140-210ppm equating to 8-12 dGH which is moderately hard, your water is somewhere in there. They are also correct that calcium and magnesium are the minerals contributing to hardness.
Before going on with this issue, I'll just mention that you also have dissolved heavy metals and sodium in the water. Not particularly high, but of concern. Copper for instance at .25 is high for fish, who need it no higher than .02 but this is not a worry as long as your water conditioner detoxifies heavy metals. Plants can take up heavy metals and detoxify them also, in addition to using some of them (like copper) as a nutrient. But the water conditioner is safer to rely on I think.
Now to the hardness. This level will provide some buffering on the pH, preventing it from fluctuating. Exactly how much I do not know, that is getting beyond my limited chemistry knowledge. As I explained earlier on, over time the natural tendency is for the water to acidify and the pH to lower. I would monitor pH in this aquarium for a few weeks to see how far that goes. The fish you have will probably be fine, but I would not add something as "delicate" [in water parameter terms] as a ray, not yet. Also, wood does help to lower pH, by releasing tannins. I don't believe this is significant, but it clearly does, so having some real wood (and that suits most fish habitats) is another positive.