At my new place the water seems to contain a lot of gypsum. I'm still
trying to guess how that is going to affect my new tank in the long
run. I think it might be harmless as the local nursery sells the
stuff as an inert additive to garden soil, but it leaves an
unattractive grey-white deposit on the bottom of a test bottle I just
evaporated. In the water heater it separates into sulfur and calcium
but I do not think that is going to happen in the aquarium.