I recently had someone by to "balance" our new pool. I could have done this myself but figured if the builder is covering it, Id let their sub use his chemicals. I tested water this morning at work. I'm a water treatment plant operator and have the best testing equipment money can buy and fresh testing chemicals at my disposal. When I tested this morning, PH was 7.5 and Alk was 90. PH was tested using Hach meter (calibrated before test). Alk was tested by titrating with Bromocresol to an endpoint PH of 4.5 This is THE way to test for alkalinity. Anyways, the pool guy was at house 2 hours later and said he got a PH of 7.9 and alkalinity of 120. How can a guy that does this for a living be this far off? Apparently, he then used acid to bring down suspected "high numbers". Also, I had tests run at Leslie's to have documentation for pebble finish warranty. I got a calcium reading of 300 by titrating using Potassium Hydroxide with a Calver indicator. Shortly after, Leslie's got a reading of 200. The point of this post is, if you get your testing done professionally, don't take their numbers as gospel. Do your own testing and if possible, use a standard to verify the numbers your getting are accurate.