Quote Originally Posted by af4444
tested some fresh tap water straight out of the faucet, ppm = 55. tried testing some tap water that has been sitting in a plastic bin for about 3 days, ppm = 75. does this make sense? shouldn't the ppm be going DOWN as chlorine and other chemicals evaporate from the water? also, considering it's city water, shouldn't the ppm be higher? read a lot of threads with people saying their water was a few hundred ppm straight out of the tap.

will calmag plus be needed??

thanks!
it goes up because only the water is being evaporated. the chemicals are not. chemicals stay the same, less water