I just upgraded full new install of 5.3 on a new SD card. All seems well except for ph reading will randomly drop either blow the correct valve or to 0 and then start working again. The real odd part about it is I have Reef-Kivy installed and running on a 7in display and it never drops out like the Reef-pi UI Does. From my understanding they are both reading from the same source. I put my old SD card with 5.1 reboot ph reads fine.