Lori.....maybe he's using Di-chlor as his shock?
I use Di-chlor,nature2,and shock my tub bout every 10-14 days. (think the shock chemical is monosodium sulfate,have to look at bottle to be sure) 2 teaspoons of Di-chlor after I use it,and I don't bother checking chlorine levels anymore.
Taylor Test kit is the 1 I use,cost 45-50 bucks....and it allows you to test all faucets of the water pertaining to spa water conditions. The paper test strips vary too much for my liking.
Nicker,get rid of Brohmine(if thats your sanitizer) and switch to Di-chlor