Prior to running my tanks with a 3 hour siesta - lights on at 7:30, and off for the night at 20:00 - I had green spot algae growth giving me spots of about 3 to 4 mm in diameter every week. Thus, scraping spots on Saturday, in between other regular maintenance tasks, only to have the 3 to 4 mm spots growing back by the next weekend.
Then, reading that a break in lighting regime could interfere with the algal cell cycle - which requires 6 to 8 hours to complete - I decided to implement a siesta. So I set it at: lights on at 7:30, off at 12:00, on at 15:00 and off for the night at 20:30.
Since then the number of spots decreased noticeably, and their diameters never exceed 2 mm. This reduced maintenance significantly. Also the growth of other algal species - hair alga, black beard and the common green furry algae - decreased. This then also reduced the requirement for chemical control - spot treatments with either hydrogen peroxide or excel.
And I had no ill effects on fish or inverts yet.