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.
Iron Content and Recommendation. One cup of boiled collard greens has a minimal 50 calories and adds 2.2 milligrams of iron to your diet. Men have the same iron requirement from the age of 19 and throughout adulthood, which is 8 milligrams per day, according to the Office of Dietary Supplements.