Thanks that's a good idea. I'll test hardness daily and see what's going on. I have only done two small changes to reduce ammonia during the cycle. Still cycling tank. The water sitting in my other tank matches the tap water hardness.I've got to say that I really really agree with Wills here. I feel that a lot of water parameter ranges stated on websites are highly inaccurate. They're almost always too restrictive, anecdotal, and unscientific. For example, I have never ever seen water parameters with citations (e.g. actual field measurements of water parameters taken from collection points for the fish, or water parameter measurements from major breeders of the fish).
Even when water parameter ranges are accurate, they ignore the fact that certain species that have been captive bred for generations can be perfectly comfortable in water parameters dramatically different than would be found in the wild.
On this forum and other forums, people make a big deal out of non-waste-based water parameters, and, for the most part, I think they're wasting their energy.
As a final note, you should definitely be basing your choices off the water parameters of the actual water in the tank, not the water as it comes out of the tap. After all, the fish will be in the tank not the tap. If the numbers in the tank are really different than the tap I would suggest measuring the hardness every day for a week (assuming you do weekly water changes) to get a clear idea of the hardness in the tank.