2nd - GDP Auto

This is the best one I've ever had a chance of using. I don't own it personally but have used air works great. PH700 Benchtop pH Meter Kit, with 3 in 1 Combination pH Electrode

just buy some cheap 100pk of strips that resolve 0.5pH. should last years. how often are you testing ph? if hydro/soilless and thenutes aren't ph-buffered, you should try a different brand and avoid the whole problem 99.99% of the time. it'll be so consistent you don't even have to test often. i test before germinating.. that's about it nowadays.

bluelab, was milion times in bucket under water - always worked after.