I've had great luck with Bluelab. pH meter and EC Truncheon. Also good to have pH drops for testing as a backup or reference, if you don't believe what you're seeing on the meter.
I’ve run into some deficiencies. I can’t see if I’ve added too many nutrients or if they need more. So just one ppm or ec and a ph. Well I’ll do some research.
i will second the bluelab suggestion. my partner dropped two cheap pH pens into the reservoir before we spent the money on the bluelab. it's been almost 3 years now and it's still going strong.
Another vote for the truncheon here. I think it was a little expensive, but it's the only one I've ever had to buy in years, and have never calibrated it or anything other than wiping it dry and back in the plastic tube till next time.
For Ph, I use the drops. Cheap and reliable. Although sometimes I do wonder how accurate or close to 6 I actually am with the "pee yellow" standard.