Thank you for all the help, as always a lot of good information. I have a lot of checking to do.
I do a regular water change once a week. I also do a top off once or twice a week depending how fast the water evapurates.
When I started my tank 2 months ago, the KH was 6 degrees, about 2 weeks ago it was still 6 degrees. It was just a recent change that brought it up to 9 degrees. However, I have not done any changes to my tank, everything is the way it was before. Would it make sense to de-chlorinate my tap water and test that for KH? If the water in the tap has increased then it would mean there is some sort of increase in the city water. Would that even be a safe assumption?