VIVOSUN Digital pH and TDS Meter Kits, 0.01pH High Accuracy Pen Type pH Meter ± 2% Readout Accuracy 3-in-1 TDS EC Temperature Meter for Hydroponics, Pool and Aquarium, Yellow Blue, UL Certified

This is the one I use: https://www.amazon.com/dp/B01ENFOHN8?th=1 and the EC meter: https://www.amazon.com/dp/B06XKMH86J?ref=ppx_yo2ov_dt_b_fed_asin_title

https://a.co/d/bU8n5pV You've asked how to test soil ph. Idk how accurate this thing is, but it might give you an idea of where you're at. You'll also want to test your runoff water (stuff that drains through your pot when you water) - test ph and ppm. https://a.co/d/iYN1p1r Test your water ph/ppm before you water and then test the runoff once youre done watering. You can google the results and see what ranges you should be in. These are all very helpful instruments if youre wanting best quality/ most yield. Your plant, pipe, and wallet will all thank you.