Your coral should be fine with alk at 10.5. They won't be happy for a few days, but it is survivable. For my timers I use Titan Controls Apollo series. They control my dosing pumps and lights.
Another thought, Paul (wall_tank) makes an auto shut off timer for dosing pumps. So, when the pump turns on, the timer starts and if it continues beyond time x (set by you, could be like 1 minute) it will turn your pumps off, and henceforth saving your tank. Not sure if he is interested in building these for people or not, but I do know that he made a post on here about how he builds them.