1 In general, the total dissolved solids concentration is the sum of the cations (positively charged) and anions (negatively charged) ions in the water. 2  Parts per Million (ppm) is the weight-to-weight ratio of any ion to water.  A TDS meter is based on the electrical conductivity (EC) of water.
Collard greens may be worth considering for health additions to your diet. These dark-green leafy vegetables provide iron, vitamin K, folate, calcium and the antioxidants lutein and zeaxanthin. They may even help you prevent gout or reduce your symptoms when you eat collard greens in moderation as part of a healthy diet.
Cooking greens are some of the most nutritious vegetables you can eat and collard greens, in particular, are packed with vitamins A, C and K, soluble fiber, calcium, folate, manganese and tryptophan - and less than 50 calories per serving. Eating your collards even helps to lower your bad cholesterol.