FUGE LIGHTING: 24 hrs vs alt

[jmarzullo]

Anyone going with 24 hour vs alternating with the main tank?? Heard any negatives??

[coralnut99]

I run 4 fuges all lit 24/7. 3 of the 4 have caulerpa mixed with chaeto, and I've never had a crash. Would alternating with tank lights be bad? I doubt it, but I'm sticking with what's worked for me for a very long time.

[jmarzullo]

thanks!

[michaeldaly]

Alternating lighting cycles are good to keep ph fluctuation to a minimum.

[EnderG60]

plants need a resipration period, so I leave the lights off for about 4-5 hours while the main lights are on.

[tgunn]

I use the same approach; my sump lights are off for a span of around 6 hours during the start of my photoperiod.

I recently decreased the lights off time to 6 hours from 12 hours and have already noticed an increase in the growth of my macroalgae.

[peteralexander]

I have mine on 24/7. The algae grows very quickly. I have a couple different types in it. I have used both 24/7 and 5 hours off. I found that having the lights off didnt increase the growth of the plants.

[Fishie Nut]

I leave lights on 24/7 because I have caulerpa and don't want anything going sexual. Light on prevents or greatly inhibits that from occurring.

[Galilean]

I have seen caulerpa go to seed with 24/7 lighting. Pruning it will prevent this however whether by tangs in the tank or by you harvesting in a sump. With regular harvests I have kept 7 species of caulerpa from going to seed for over a decade even through many transplants to new tanks.

I think that 24/7 lighting will cause most algae to grow faster than an alternating cycle. For macroalgae there is a saturation in the sense that the plant may grow a little less per hour of light, but grow faster overall because there are more hours of light. It might be that the fastest growth for a particular algae would be 22 hours of light or 20 but you would have to actually dry it out and weigh it to be certain. There is also a saturation for light intensity for macroalgae, but if don't have MH you won't reach it. Even MH lighting, even full tropical sun won't saturate micro-algae provided the temperature doesn't also sky rocket.

In principle alternate lighting can lead to more stable pH, but I get day/night variations as small as 0.1-0.2 pH with 24/7 lighting already because there far more plants in the sump than in the main tank. For alternate lighting to be more stable you would have to precisely balance the tank plants with the sump plants. It's easier to get stablity by just having a lot more plant production in 24/7 lighting in the sump.

With no sump lighting and 12 hour day/night cycles on a well stocked reef I would typically see a day/night swing from 8.1-8.5 pH.