What does BOD and SOD mean in water?

Your above ground sand filter is running at too high psi what do you do? How do you remove a salt stain from a pebblecrete pool? What is the English meaning of Padre Island? Do salt systems permanently discolor plaster pool surfaces? How can you bring down the chlorine level in an above-ground pool? How do you find a tiny hole in the top inflated ring of a intex above ground pool if you are having to inflate the top ring daily and can't locate a hole and you have tried using soap and water? Can you leave the bottom part of an old pool liner when installing the new one? What does the idiom under the water mean? What is hydroism? Is krystal krete a good pool surface? How is rowing adduction? What does to twist a cloth to make water come out of it mean? What is a similie for this expression - the sea crashed on the rocks like? What happens if you get an American girl dolls wig cap wet? How does one install a bathroom heat lap? Should you breathe in with your nose when doing the front crawl? What are the settings for the dial a flo ports on hayward ec 65? When do you do flip turns in an IM Please help I have a swim meet in a few days? What happens if a swimmer breaks each swimming rule? What is the longest distances swam?