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.
Collard greens are packed with pro-vitamin A (in the form of carotenoids), with one ounce of cooked and drained collard greens delivering a whopping 45% of the Daily Value for pro-vitamin A. Carotenoids are involved in numerous bodily functions, but they are probably best known for their ability to protect eye health.