Abbreviations - 2012

[waterbear]

Here is what I have for now:

CH or CAL for calcium hardness, which is conspicuous in its absence above (but Anna K has a vinyl liner pool so it's excusable!)
ppm is parts per million and it is a measurement of the concentration of the different chemicals in the water. It is the same as 1 mg/liter or 1.5 grains/US gallon or .0034 oz./US gallon. Sometimes ppt (parts per thousand) is used for salt concentration and ppb (parts per billion) is used for phosphates.
Trichlor--a slow dissolving stabilized chlorine source, often in pucks or sticks that adds 6 ppm CYA for every 10 ppm FC added
Dichlor--a fast dissolving stabilized granular chlorine source that adds 9 ppm CYA for every 10 ppm FC added
Cal Hypo-- an unstabilized granular chlorine source that adds 7 ppm CH for every 10 ppm FC added and commonly sold as "shock"
DE--diatomaceous earth, used as a filter medium in some pool filters (DE filters) and as a filter aid in sand filters
OTO--a test for total chlorine (TC) that turns shades of yellow to orange and brown at very high chlorine levels. It is bulletproof in that it does not bleach out at high chlorine levels and that it will always change color if chlorine is present. It is good for a quick daily chlorine check to make sure everything is OK.
DPD--a test for both FC and TC that turns shades of red and the most common test used in better drop based kits and most pool store testing (unless they use strips). It will beach out at high chlorine levels (usually staring around 10 ppm) so it is not good for testing very high FC levels. Many men have difficulty distinguising between the shades of red.
FAS-DPD--A drop counting test (titration) for FC and CC. It can test chlorine levels up to about 50 ppm with a precision as great as .2 ppm. It is a better chlorine testing method and can even be used by someone who is colorblind since the color change from pink to colorless is easy to see. This, in combination with OTO for daily tests, is the preferred method of testing chlorine.
HEDP--a metal sequestrant that is sometimes needed if there are metals in the water.
MPS or KMPS--a non chlorine "shock" (oxidizer) that can be useful in hot tubs or indoor pools that have a problem with persistent combined chlorine. It is not a sanitizer in swimming pools but in conjunction with silver ions and hot water is an EPA approved sanitizer for hot tubs. It will test as CC on FAS-DPD testing and as TC on DPD and OTO testing so it does interfere with chlorine testing unless special procedures are used.
UV--ultraviolet light. UV can be useful in indoor pools to help combat persistent combined chlorine. It's pretty much useless in outdoor pools that are exposed to sunlight.
MSDS--material safety data sheet is an information sheet that must, by law, list all hazardous ingredients in a product. Only the hazardous ingredients need be listed and terms such as "proprietary mixture" or a general description of the other ingredients is permitted.