I use some really expensive pH meters at work. We re calibrate daily and replace them yearly. They don't last for some reason. When we don't need exact numbers we use API test kits. They aren't great but are consistent.
I have 2 other ads for Zoas and favias. I mostly have lps and Zoas but a couple acros and shroom. Not to many in Rockland county. I’m only aware of a couple.