Swimming pools blog

I’m trying to get our pool back in balance - we just had it built last year,
so this is out first spring. The alkalinity and pH were both very low, I’m
working on those (doesn’t pH == alkalinity/acid???? Why both readings? If
there’s a primer on pool chemistry on the web somewhere, I’d love to know
about it.
One thing confuses me - I’ve got some test strips left from last year, and
they read very low free chlorine. I bought some new test strips, and they
read high but OK free chlorine. The only difference I can see is the old
strips only have 3 indicators, the new ones have 6. Any advice/explanation
is welcome!
Thanks,
Harry Boswell