I started a SLAM on Thursday. It rained non-stop for 12 hours during the SLAM on Friday and I didn't go out and test or add any chlorine during that time. I went out an hour after it stopped raining and tested the PH since I was worried that the rain increased it. It said that it was 8.0 so I lowered it (it was 7.4 before starting the SLAM). I stupidly forgot to test the chlorine level to make sure it was lower than 10 when I did this, however. When I went to test the chlorine an hour after adding the muriatic acid, I discovered that the chlorine level was actually 12 ppm so the PH test probably wasn't accurate. I still can't believe that it only went down 4 ppms in 14 hours but that is what the test indicated. I went ahead and resumed the SLAM since I didn't want to miss out on the benefits of a night-time shocking. If PH was actually still 7.4 where it was before it started raining, I probably added enough acid to lower it to 7.0 (or possibly a bit lower) according to the pool math calculator. TA is only 50. Do I need to let the chlorine drift down below 10 today so I can retest it, and then bump it up if needed? Water went from a dark green to a pale green overnight, and I can now clearly see the bottom so I hate to delay the SLAM to test the PH unless it is needed. Since the chlorine raises the PH, do I even have to worry about PH of 7.0 or even 6.8 causing any problems? I tested the water at a 14 ppm chlorine level a little while ago and it says PH appears to be around 8.0 again, but I know this isn't accurate due to the high chlorine level.