i just spent 3 hours reading everything posted in this forum regarding testing water. the only conclusion i have come to is no one here has come to a conclusion. i maintain over 300 pools on long island and have the answer for everybody. i have used every single testing gimmick and professional kit on the market, and the only consistent result is no test kit gives a consistent result. you can test the water 5 times at the same time and all the readings will be different. the best advice is if you are here in this forum for a little advice about what to use on your new pool, is get yourself an inexpensive 7 dip test strip, and stay out of the pool store as much as possible. testing your pool water is like taking your temperature. it will be different every single time, no matter how accurate the thermometer and adding chemicals to the pool when your readings are only slightly off is like taking medicine when your temperature is 98.5 or 98.7. stick with the 7 dip strip and only go to the pool store to verify your results if you are having a problem with the pool. the chemical advice on the other parts of this forum are excellent, with nearly perfect information on the use and application of chemicals. i would advise all new pool owners to remember that anything you put in your pool water will always be there, only pure water will evaporate so be careful what your buying and adding because years later it may still be there.