Need advice on water

I made a post in the Water Quality/Chemistry Report thread in the Recipes/Ingredients forum, but I think no one is looking over there, so I'll link to it here:

https://www.homebrewtalk.com/f12/wa...-report-thread-101510/index4.html#post2283622

I have made a spreadsheet with 3 1/2 years of monthly water reports from a local water treatment facility (Wylie, Texas), and have provided graphs of this data (one graph per mineral) below the tabular data. I see a lot of variation in some of these mineral levels and don't know if this is typical. I need to get some advice on whether I can use this water successfully by using an average of the last few months, or if the variations are so large that I would do better to start with RO water and build my profile from that.

Note - I believe the last 11 months of data for Total Alkalinity as CaCO3 is wrong in the original reports and on the graphs in my spreadsheet (it shows up as the same number as HCO3 mg/L) and should be multiplied by 50/61, so mentally move those last 11 points in that particular graph downward by about 1/6.

Thanks in advance for your help.