Being a disorganised person I've mislaid the indicator and instruction page kindly sent to me earlier in the year (hope the sender doesn't read this

Background to this post:
I've noticed my tap water alkalinity in 2008 has varied between 52 and 117 according to my report


Can't live with this and so want to test the HLT contents before each brewing. Last brew I did I added CRS in line with 82mg/l HCO3 and mash ph was 4.8-ish, boo.
Many thanks in advance.