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.
Adjust Your Total Alkalinity. To increase calcium hardness you'll need calcium chloride. Calcium Hardness. You can swim 2 hours after adding, but if you can, allow for one full turn-over of the water. A turn-over is a full and complete filtration of all of the swimming pool water, normally about 10 hours. This is why you'll want to make any adjustments at night. A pool shock is a different story.