Originally Posted by BBradbury
Unless you keep rare fish, you don't need to be concerned with pH, hardness or any of that kind of thing. As long as the water chemistry remains fairly stable, your fish will adapt to your tap water. Just treat it for the standard toxins like ammonia, chlorine and chloramine.
Large, frequent water changes will also maintain the water properties.
Have been keeping tropical's for nearly 40 year's, and there are lot's of fishes that will manage in moderately hard to hard water, and more than a few who thrive in soft, acidic water,and do poorly over the long haul in hard alkaline water.
Keeping soft water fishes in hard water, or vice versa,serves no useful purpose, and is often the difference between fishes that thrive,,,and those that last but a few week's month's IME.