Thought this may be of interest. I'm in West Dundee, IL a far northwest suburb of Chicago. We have our own water supply and filtration plant. The village gets water from the Fox river in which the town borders. I have an HTH kit from walmart that I've been using this year. To satisfy my curiosity, I did a test today on the water from our tap and here's the results:

Cal - 80
PH - 7.8
Alk - 360
TC - .5

This may explain the problems I've been having with lowering Alk this year. I didn't test for CYA, I didn't see the need. Only did Total Chlor, since thats all the test provides. I usually figure Free Chlor on my test strips, which is the only thing I use them for anymore. Does anyone else have high alk from fill water, and if so, are there any preventative techniques or tricks to keep the alk from rising everytime i have to add water after a backwash? Thanks