You can buy a cheapo meter online for under $50, that will work for you. I paid under $20 for my current meter, and I've had it for over 1 yr. now. I know folks with quality meters and my cheapo, measure's same numbers as his, every time. Piss's him off !! I was growing in that nasty FF Ocean forest soil, till I met Cultivator & he introduced me to coco coir, and it was the best thing that's happened to me. If you ever want to try a coco grow, Cultivator is the man to learn from !! I don't think I'll ever go back to FFOF, or any other media. I've been at it for a little over 1 yr., and I'm getting it dialed in now. Thanks Cult !!