For those growing photo periods, and using digital timers........do a reset on them to default. Mine had values already set in a second program and I didn't know it. My plants should have been on 12/12 2 weeks ago! Got up at 2am the other morning and decided to peak into the growroom and saw the light on........grrrrrrr.... did a reset, now on 12/12. BUT...... my plants are huge and this isn't even stretch yet..........