Yes, to do this what I would do is write a “Custom Program”, for which there are templates already in the code. Make some counter that increments by 1 each experiment loop, and when it gets to 180 (60*3) change the OD set-point to 0.01. Then, have it stay in that state until the desired OD is reached (e.g. do a check that OD<0.01). Once this is achieved then put the OD setpoint to something large (e.g. 10) and re-start your 3 hour timer.