Algae yield in 18hr on/6hr off versus 3hr on/1hr off light c

[Broder]

The weights are now in. These weights are of algae harvested and dried on a weekly basis.

Weekly harvest in grams during 18hr on/ 6hr off light cycle.
week 1.) 29.4g
2.) 30.0g
3.) 39.8g
4.) 29.8g
total: 129g

Weekly harvest in grams during 3hr on/ 1hr off light cycle.
week 6.)33.8g
7.)37.6g
8.)21.8g
9.)34.6g
total: 127.8g

The experiment was conducted with new lights. Feeding was kept as uniform as possible in the absence of measuring. There were no major variations in bioload or water parameters. Nitrate and phosphate readings remained a constant 0ppm. Water changes were a uniform 15% NSW per week.

This is by no means a definitive or scientific experiment, but I think we can conclude that a 3hr on /1 hr off light cycle has no measurable benefit.

[kcress]

I'd agree with your assessment and thanks for the not insignificant effort!

I have to wonder about the cycling of the lights for the longevity of CFLs. Most I see croak, do it on turn-on which leads me to think that's the most stressful part of operation - as long as they aren't having heatstroke.
I'll point out the obvious that 6 on 2 off would thrash them a little less. :)