Gabriel_swe:
I assume you are controlling a fan and h is humidity and t is temperature.
If you should have a gap between your values or not is something you will find out with trial and error. I would expect a small air volume and powerful fan need a smaller gap and maybe shorter time.For another relay I think a second counter is needed.
Yes a fan for a vivarium, another relay for a fogger. The volume is quite small in relation to volume of air moved. So have reduced counter seconds down to 15 , using a small pc fan 60mm might even go smaller but will possible prefer to run at a lower speed. Trail and error is going to be everything before I put anything in there. Might also need a heater but if I can find a happy medium with a heater then control temp by venting I should get good air circulation and safe having a heater on the sketch too. But then if the fogger will be on to increase humidity.... Going to have to play with room temps too and how this effects with other perimeters. Many thanks all that has helped this noobie.