I'm not sure of a one time setup can really be relied upon. I found yesterday that my tap water ph went from 7.1 to 6.5 which explains why my usual water adjustments were off. I wasted about 1 hr after I had drained the HLT and reheated back to strike temp.
On the ph meter, I've got a Hanna phep5 the one with 0.05 ph accuracy which works great. Money well spent as it made a huge improvement in the taste of my brews. Cost about $80.