This chapter describes the principalorganizations involved in national security space activities, concentratingon the Executive Ofï¬ce of the President, the Department of Defense, theIntelligence Community and the Congress. It provides an assessment ofhow well this structure now serves the nationâs interests in space.
Reduce Pool Water Hardness. 1  Take a water sample from a depth of at least 12 inches from the water surface. 2  Add a reagent from a hardness test kit to the water sample and check the result against the guide provided by the test kit manufacturer. 3  Drain some of the water in the pool if the water hardness level is too high. Add fresh water to replace the water you remove from the pool. Collect another sample of the pool water and conduct the hardness test again to check that the hardness is between 200 to 400 ppm.
Rain water. Rain water is acidic, so it will naturally lower your pool and spa waterâs pH. Remember your pH should not fall below 7.2 or your water can become corrosive and cause damage to your poolâs surfaces and equipment. Pool water with low pH is also uncomfortable for swimmers, and chlorine will expend itself more rapidly.