This is the pH meter i swear by and doesnt fail me as long as calibrated
Digital pH Meter with ATC pH Tester, 3 in 1 pH TDS Temp 0.01 Resolution High Accuracy Pen Type Tester, Water Tester for Water, Wine, Spas, Aquariums https://www.amazon.com/dp/B08RD488NP/ref=cm_sw_r_apan_glt_fabc_XE5D47FAH2Z5NR919V3W?_encoding=UTF8&psc=1
I don't live in that area but honestly I don't think you need professional cleaners unless you really don't want to do anything yourself. It's not that hard to clean a used tub.
You'd probably just want to
Water balancing can be a little bit of a learning curve. You can google around for hot tub water balancing and find plenty of guides. I just don't recommend the test strips for pH, etc, at all really. I do recommend picking up a digital pH meter like this one and a Taylor test kit like this one.
I also have a preference for bromine over chlorine for my sanitizer, since it's more stable over time, works in a wider pH range, and ultimately requires less maintenance.