Chiller not holding temperature after power failure

[Ludecrasher]

Hello all, I just purchased a JBJ 1/10hp chiller and works great, BUT I just had a power failure and when I woke up my water temp was at 69 degrees!! The settings were set to .5!!!! If I weren't home ALL my fish and corals would've definitely died. What can I do to prevent this from happening again? I'm scared leaving the chiller on now when I go to work.

 

[Pseudo69]

Use a controller. Apex ,profilux, reef angel or a simple Ranco controller.