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.
Add the greens. Cover the pan and cook until tender. Chard and beet greens will take 8 to 10 minutes; kale, mustard, turnip, and collard greens will take 20 to 25 minutes. Drain the greens well in a colander, pressing to remove excess liquid. Toss with 1 tablespoon butter or olive oil, if desired, and season to taste with salt and pepper.