When i change water for my fish, i go buy drinking water, but is wondering if tap water is safe? If it is, what is added in the water to make it safe? Thanks
Most tap water is bad, and it contributes to massive algae growth. Check with your city water dept online to see the levels and determine if it's suitable for your tank.
I wouldn't use tap water because it has many nutrients that kill sensitive inverts and it also contains many other chemicals that can't be neutralized. I use a RO/DI unit.