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.
To boost your daily nutrition, aim to eat about 2 cups of dark, leafy greens like collards every day. Two cups of raw greens is equal to 1 cup of vegetables, and 2.5 cups is recommended daily for a 2000-calorie diet. Cooking tip: Quickly blanch the leaves in boiling water, then chop them and add them to whole-grain or lentil salads.