I've seen posts that a period of darkness within the overall photoperiod is not known to enhance plant growth.

But my question comes from the other direction - is there any basis to think a period of darkness is *not* desirable? (algae, plant growth, fish, etc.)

Goal is simple. I recently delayed light onset at beginning of day in order to shorten overall photoperiod (which is currently from 11am-8pm). But now lights are out before I go to work, and I enjoy my morning coffee looking at tank.

I would like to:
Lights ON 6-8am
Lights OFF 8am-1pm
Light ON 1pm-8pm

Curious of anyone does this, or has suggestions/cautions. Duration of first ON phase not relevant, as long as lights come on when I do


Thanks,
growitnow