I'm with Majorduke. I recommend a digital. Many models to choose from.
For a few years I used Milwaukee portable units and they worked for me. It was about $20.00 and had replaceable batteries and was a pretty accurate pH meter IIRC. I now use a Milwaukee MC120 with a submersible probe. It's great and I can monitor it 24/7. I also got one of their TDS meter with a submersible probe. I am looking for a submersible thermometer that's reliable. As I said, digital is much better IMO and there are so many models to choose from.
I wish you luck.