Pakistan's natural resources range from natural gas reserves, vast land, coal, petroleum, copper, salt and iron ore among others. It has the second largest salt mines in the world, as well as worldâs fifth largest gold mines.
Leslie's 14427 Hardness Plus, 25 lbs. Leslie's 14428 Hardness Plus, 45 lbs. Keep your calcium hardness at proper levels at all times to help protect your pool, water, and pool equipment. The calcium hardness level in a pool does not increase rapidly, but it is good practice to check the calcium hardness every month. Adding 1-1/4 pounds of hardness plus to 10,000 gallons of water will raise the calcium hardness by 10 ppm. **The minimum level of Calcium Hardness is 150 ppm.
Protecting the Hot Tub From Water Impurities. 1  1. Measure the calcium hardness of your water when cool. Turn off your heater and let your water cool. 2  2. Add hardness increaser to low calcium water. You want your calcium level to be between 200 and 400ppm. 3  3. Remove hard water if too much calcium is present.