You need to pin down the GH and KH (Alkalinity) as others have said. When you take a water sample (of your tap water on its own), the GH is the more important but it would be very helpful to know the KH (Alkalinity) as well if they will test both. Make sure you get the number (write it down, don't leave anything to memory as this is very important data) and their unit of measurement (it will be something like ppm, degrees, mg/l). Without both the number and their unit to measure, we can't proceed.
You mentioned adjusting the pH earlier in this thread...do not. The pH is connected to the GH and KH and once we know these it will be easier to asses things.
You mentioned adjusting the pH earlier in this thread...do not. The pH is connected to the GH and KH and once we know these it will be easier to asses things.