Originally Posted by kelben
sorry about the font... I hate that too, when you can't see the darn post!!!
I checked the water just now, (with API 5 in 1 test strips) and the GH is 120 and the KH is 180-240. I don't know what that means exactly, but I know it's hard water. I would love the whiptale catfish, the profile puts it a little out of my water parameters though.
From those numbers, it is not hard water. The GH is the mineral hardness, and at 120 ppm equates to 7 dGH, which is at the high end of the "soft" range.
The pH can be based on other factors, namely, what is actually causing it to be high at 8.0, and while this is often the GH it is not here. There may be other substances in or added to the water to create a high pH.
The KH is high, at 180-240ppm, or between 10 and 13 dKH. This has no effect on fish whatever, but being bicarbonate hardness it does work to keep the pH stable. This means the p|H is very unlikely to lower much by natural means in the aquarium, unless the KH is "diluted" with pure water.
You can read how all this relates here: http://www.tropicalfishkeeping.com/f...quarium-73276/
So, back to the fish. As the gourami seems to have no trouble, the suggested corys shouldn't either. The GH is not high and that would affect them more. And I wouldn't rule out the Whiptail. The pH range in the profile has to have a limit but it is not cut in stone, and only because you have soft water I would suggest this species also is likely to be OK.
Last suggestion, as test strips can be inaccurate due to this or that, I would confirm the GH and KH with the water supply people, just to be sure.