EC, PPM, TDS for beginners

I would like to put this out for new farmers. Invest in a Decent PH Pen that will read EC and temp. The pen while in EC may read as COND. This in my opinion is the most important 3 readings you will need. And start your reading with EC there are many charts on internet that will tell you your EC Level for your plants growth stage. And then PH your nutrient water again charts on internet for your grow medium as with temp. Of your water.
PPM’s and TDS will fall in line with YOUR EC READINGS SO DO NOT GET CAUGHT UP IN THOSE READINGS. And if your EC is too high add more of the same water that you used to make up your nutrients this is the only way to lower your EC. If your EC Is too low and in small amouts of base nutrients again charts are on internet. I hope i have helped anyone that was lost in the world of reading what and when. No one told me about this when i started outi would have been successful alot sooner. Happy growing ILGM !


So you are saying go by EC and not ppm’s? Its my uneducated understanding that the two are more of the same.

I should add that i rarely check input ppm’s, i only check the ppm’s of my run off. And i will then either do just water, a 1/2 strength feed or full strength feed in my next watering.

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EC means ‘Electrical Conductivity’ and is measured in microsiemens. An EC of ‘1’ equals a PPM of 500 on the NACL scale (USA). An EC of ‘1’ reads 700 on the Potassium Chloride scale or KCI (UK and Canada). They are all measuring the same thing.

PH readings also use EC and are an approximation like TDS.



Yup: what I said.


I keep my EC between 2.8 - 3.2 with my own sweet to the 500 scale.
I also track my PH as it can get way out of whack and change the EC.
TDS (ppm) are directly related to my EC.
I check all of them to look for variations in my pen, which usually means i need to calibrate it.

I use an Apera pen. Definitely worth the money, especially for a hydro system.