Refugium Lighting — Opposite Display or 24/7

[kittenbritches]

Do you run your refugium light 24/7 or on a schedule opposite your display tank, and why?

Do you think there is any harm or benefit to one schedule over the other?

 

[CoralNerd]

Opposite of the display but if the DT has algae issues 24/7

 

[PeterC99]

Opposite display. Chaeto grows very well and need to harvest it every other week. No algae issues with my Radions set at peak 80% Light Point Intensity for 4 hours.

 

[Rmckoy]

I run mine the same schedule as display .
Only because I didn’t want to set up a separate timer .
ideally I have read the advantages of running it on opposite schedule is said to help regulate ph stability .

 

[Subsea]

Do you run your refugium light 24/7 or on a schedule opposite your display tank, and why?

Do you think there is any harm or benefit to one schedule over the other?

After 50 yrs of Reefing, I have run every schedule.

Initially, I ran opposite photo-cycle to dampen pH swings. Oxygen depletion is more important than pH swings. Instead of trying to supple oxygen and remove carbon dioxide using photosynthesis in a small refugium, I suggest maximizing gas exchange with robust circulation at the display tank surface or tumbling water from display to sump/refugium.

Twenty four hour lighting was initially used to prevent fast growing Caulerpa’s from going sexual. Pruning regularly prevents Caulerpa from going sexual.

I now run cryptic refugiums with zero light.

 

[SDK]

Running an opposite schedule did decrease the PH swings in my tank, and kept the PH higher overnight. This is a benefit during times of the year when my house is sealed up.

I verified the above with an Apex…..

 

[Subsea]

@kittenbritches

In composing my response to you, I looked for your tank thread for clarity on responding to your question specifically with your system. Do you have a tank thread that outlines your system. Best I can tell, you made a major upgrade two weeks ago to convert 40G breeder into an SPS tank. Now you want to optimize the use of an algae refugium?

What is your experience level in reefkeeping? The reason I ask is because algae filtration does much more than mitigate pH swings by consuming carbon dioxide and producing oxygen. All photosynthetic organisms consumes inorganic nutrients with a byproduct (exudates) of dissolved organic carbon, DOC.

Coral DOC is mostly composed of lipids & proteins while algae DOC is mostly glucose. All are necessary building blocks.

As you have already found out on other threads, you will get numerous conflicting statements because numerous styles work. What are your current nutrient management methods?

 

[Subsea]

Since this was listed as a poll, the op asked what schedule & why.

Why does a refugium need to be photosynthetic? I understood refugium to be a
”refuge from predators”

First, I think pH fluctuation as being a bad thing in our reef tanks is overblown & incorrect, in most cases. Healthy wild reefs pH fluctuate from 8.2 - 7.8. I actually encourage pH swings with a cryptic refugium. In the depths of display tank sandbeds, low pH performs passive alkalinity bufferring & trace mineral addittion by dissolving aroggonite.

Second, in addittion to maximizing diversity of micro inverts, cryptic refugiums proliferate cryptic sponges which complete biofiltration of all DOC at a removal rate
5 fold more efficiently than activated carbon which is 8 fold more efficient at removing DOC than protein skimmers.

for unlit refugiums is in addittion to maximizing biodiversity