EC/TDS Readings

I go by ppm. They're both the same just different conversions. I think the most important thing if you're using one is to use it daily. Take a reading before the feed and after feed every day. This will get you to understand how it works the fastest. Some ppl make up a feed then RO water their plants...this is a poor method as the plants need really can change on a dime

EC stands for Electrical Conductivity and is measured in mS/cm or millisiemens per centimeter. TDS stands for Total Dissolved Solids and is measured in PPM or parts per million. TDS is acquired by taking the EC value and performing a calculation to determine the TDS value. Because TDS is actually a calculation it is really only a guess at what the nutrient concentration is. On top of that, there are three different conversion factors to determine TDS and different manufacturers use different conversion factors. In other words you could test the same solution with two different meters and get two totally different readings. But the EC is read the same by all meters the only difference is the conversion factor.The solution is simple, use EC. With EC, no conversion is required so all meters will read the same regardless of the manufacturer. Good luck mate