you can set it to stay off for 6, 8, 10, 12, hours
http://ecotechmarine.com/wp-content/uploads/2010/05/FULLMANUAL_Revision1.1.pdf
This is a full manual tells you how to do it
How do u set it for 6/8/10/12 hours?Although the key is you have to START it at the time you want it to go in to night mode. If you want night mode to start at 9PM, you have to set it AT 9pm for it to go in to night mode at that time. Then choose how long it is the night mode 6/8/10/12 hrs and it will rinse and repeat UNLESS you disconnect it OR the power goes out.
not to hijack, but is there a good reason other than noise for night mode? It's not like the currents in nature change much at night and I think my SPS like getting whipped around when they are fully open at night. Just curious if there is a biological advantage to a less active current at night.
You're right. I use night mode simply for the fish so they can sleep easier. Otherwise I wouldn't use it.