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 full of iron. Collard greens are a type of cabbage that make a healthy low-calorie addition to any meal. Dark leafy green vegetables, like collard greens, are loaded with iron. You need iron for several processes, however, iron-rich plant foods should not be your only sources of iron. Optimal absorption of iron from collard greens and other plants is dependent on several dietary factors.