PH up and down is worth it. It's precise and well tested etc.

I bought a Hanna GroCheck continuous meter. It's like $120 at some pretty big online hydro stores (bghydro.com). I keep it in my water 100% of the time. I'm lazy like that

Also when you get a meter, take note of which calibration fluid you'll need for the EC/TDS and buy some. Buy some PH fluids also.
MisterE Reviewed by MisterE on . Somebody Please Explain..... I have been reading alot about EC, PPM, TDS meters but still dont quite have a good understanding on which meter would be right for me. I have read that PPM and EC basically read the same thing but you have to use conversion/mathematics. I will have a simple system 4 plants max fed from a 10 gal res. I purchased 3 part nute system from advanced nutrients. Alot of these meters are pricey but they say well worth it. What do you all use to keep your nutrient to volume of water accurate. What is a Rating: 5