I just got my Hanna HI98121 yesterday along with bottles of calibration, cleaning and storage liquids. My pool is kept at 95 degrees and receives heavy use. They recommend that the PH function be calibrated every time I use it and they also say that after calibration, I should just put the probe in the actual pool water so the temperature is accurately recorded. Hanna claims that PH is temperature dependent and unless the temperature is known the reading is not meaningful. I ran my first test this morning and got ORP of 735 and PH of 7.55. The water is very clear and has no chlorine smell at all. The users are very happy with it. I'm just wondering if anyone has an opinion about these numbers? Is an ORP of 735, PH of 7.55 at this temperature considered good, OK or something else? Performing the test has to be done on my knees so the probe can be put in the pool water right after calibration. Also, the numbers take a few minutes to stabilize. They have a little clock on the screen and they say to keep it in the water until the clock disappears. It's really pretty easy to use. I'll post a photo of it from my phone.