Splitting light cycle

alexwbush · 07/02/2015, 08:40 AM

I am moving electricity to a time based model where mid day costs more than off hours and 2-7pm is peak expense.

What I am thinking of doing is splitting the light cycle before and after peak, allowing the tank wider temperature ranges, and turn off some pumps during peak hours. Any issues with splitting the light cycle? And other ideas to conserve? I already use radions (LEDs).

kurt_n · 07/02/2015, 09:36 PM

I don't have any scientific studies to back it up, but I wouldn't think it would be a good idea - from a coral health standpoint. Corals have pretty much evolved assuming they're going to get 12 hours of light, starting low, peaking midday, and ramping down. They're looking for that 12 hours of continuous light, not necessarily six 2-hour cycles, or two 6-hour cycles. I would suspect the chemistry going on inside the coral isn't going to be the same in those different scenarios, even though the total light time is the same.

Google "Dana Riddle" and look for some of the papers/articles he's written on coral lighting. I'm thinking he might've touched on that question somewhere.

alexwbush · 07/02/2015, 10:07 PM

Interesting. I'll look into that. I'd read some articles that suggest split light cycle actually improves growth.

zachts · 07/03/2015, 10:36 AM

Try it and see how the corals respond. Nature does cause that kind of cycle from time to time with clouds and storms etc, just not all the time. Algae provides the main food source to coral so as long as it gets enough light to photosynthesize it should be fine.

Personally I think I'd just shift your mid day light peak before or after peak electrical rates kick in. Ramp up fast in the morning and then drop back down before high rates kick in to a nice viewing level for the remainder of the day, or the reverse and end on a high light level with quicker ramp down. 4-6hrs peak lighting is fine with enough intensity during that time to make the SPS happy, then dropping down to a "cloudy" day level for the remainder (same principal as people running MH), just enough light to keep the algae from shutting down photosythesis. You'll see much greater polyp extension in the evening viewing hours with this lower light level, which may be very interesting to observe and make for easier feeding of LPS and SPS.

Make the shift slowly over a couple weeks so things can adapt to the new light cycle and just keep an eye on how things are looking.

stancfii · 07/04/2015, 09:04 AM

There are a few old threads from people here who have done it with success. 4hr on/off is just fine. The biggest downside is bulbs starting twice a day which will decrease bulb life.

zachts · 07/04/2015, 11:44 AM

The OP is using LEDs so no issues with on/off.

07/02/2015, 08:40 AM	#1
alexwbush Registered Member Join Date: Jan 2005 Location: San Diego, CA Posts: 453	Splitting light cycle I am moving electricity to a time based model where mid day costs more than off hours and 2-7pm is peak expense. What I am thinking of doing is splitting the light cycle before and after peak, allowing the tank wider temperature ranges, and turn off some pumps during peak hours. Any issues with splitting the light cycle? And other ideas to conserve? I already use radions (LEDs).

07/04/2015, 09:04 AM	#5
stancfii Registered Member Join Date: Jan 2005 Location: Birmingham, AL Posts: 583	There are a few old threads from people here who have done it with success. 4hr on/off is just fine. The biggest downside is bulbs starting twice a day which will decrease bulb life. __________________ 180g SPS -3 x 250w Radiums, 2 x VHO actinic, DIY RB LED strip, and a EuroReef skimmer modded with a DC pump.

07/02/2015, 09:36 PM	#2
kurt_n Registered Member Join Date: May 2006 Location: WA Posts: 2,592	I don't have any scientific studies to back it up, but I wouldn't think it would be a good idea - from a coral health standpoint. Corals have pretty much evolved assuming they're going to get 12 hours of light, starting low, peaking midday, and ramping down. They're looking for that 12 hours of continuous light, not necessarily six 2-hour cycles, or two 6-hour cycles. I would suspect the chemistry going on inside the coral isn't going to be the same in those different scenarios, even though the total light time is the same. Google "Dana Riddle" and look for some of the papers/articles he's written on coral lighting. I'm thinking he might've touched on that question somewhere.

07/02/2015, 10:07 PM	#3
alexwbush Registered Member Join Date: Jan 2005 Location: San Diego, CA Posts: 453	Interesting. I'll look into that. I'd read some articles that suggest split light cycle actually improves growth.

07/03/2015, 10:36 AM	#4
zachts Registered Member Join Date: Mar 2005 Location: St. Louis, MO. Posts: 3,259	Try it and see how the corals respond. Nature does cause that kind of cycle from time to time with clouds and storms etc, just not all the time. Algae provides the main food source to coral so as long as it gets enough light to photosynthesize it should be fine. Personally I think I'd just shift your mid day light peak before or after peak electrical rates kick in. Ramp up fast in the morning and then drop back down before high rates kick in to a nice viewing level for the remainder of the day, or the reverse and end on a high light level with quicker ramp down. 4-6hrs peak lighting is fine with enough intensity during that time to make the SPS happy, then dropping down to a "cloudy" day level for the remainder (same principal as people running MH), just enough light to keep the algae from shutting down photosythesis. You'll see much greater polyp extension in the evening viewing hours with this lower light level, which may be very interesting to observe and make for easier feeding of LPS and SPS. Make the shift slowly over a couple weeks so things can adapt to the new light cycle and just keep an eye on how things are looking.

07/04/2015, 11:44 AM	#6
zachts Registered Member Join Date: Mar 2005 Location: St. Louis, MO. Posts: 3,259	The OP is using LEDs so no issues with on/off.