Planted Tank Enthusiast
Join Date: Aug 2006
Location: Cincinnati, Ohio
I have to conquer here. My water is massively hard too. My test kit only goes up to 200 ppm GH, and the test shows that, so I just assume it's hard.
My best advice is don't tinker with it. If you want to start using RO water, you're really adding on a lot more work for yourself. You need someplace to store the RO water, then you have to do your waterchange, add in RO water or mix it with tap water, but you have to make sure you're close to your target value etc.
I keep angels in this water with no trouble, my friend keeps discus, and I've even talked to 2-3 people locally here that said they have very successful CRS colonies in the water. So unless you have your heart on high-grade CRS, or breeding Discus, or some sort of application which really needs soft water, I wouldn't go through the trouble.