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.
Cook with both the leaves and stems of collards. Photo Credit Brand X Pictures/Stockbyte/Getty Images. Like broccoli, Brussels sprouts and cabbage, collard greens have a bitter taste because they contain so much healthful calcium. There are lots of ways to tone down the bitterness. Because they have plenty of vitamin A, vitamin C, folate and fiber in addition to calcium, collards deserve a place in your diet. Choose bunches with crisp, dark green leaves with no yellowing around the edges and cook them within five days of purchase.