As per a post by
@saltyfilmfolks
" You can but I wouldn't. Photosynthesis does need a rest.
by Randy Holmes-Farley For many aquarists, pH is not something that they have much experience with aside from their aquarium. For many, pH is almost a black box measurement: something to be considered, but whose physical meaning makes little sense to them. This article will Read more here...
www.reefedition.com
http://reefkeeping.com/issues/2005-08/eb/index.php "
If you're actually looking for citations.
Yes you can stick a light in front of macro algae 24/7 and never turn it off but with all the research I've done in macro algae reactors, and 10 years of messing around with them from custom made 416s to the pax bellum c-36 there are benefits to giving the algae dark period. Lighting and nutrients can affect things, but the end of the day, photosynthesis.... I can't think of a place off the top of my head anywhere in the world where the sun is present 24/7 and plants thrive. The life of the macro algae may not be at risk immediately but I find better performance and growth running with some dark time. You always have to cull out a certain amount of algae that's just no good when pruning your reactor and I've done it enough times to get an idea of what might affect that bad portion, the only based on correlation. Now I'm using lights that minimize at perhaps 24 Watts and go well above that so heat can clearly play a factor too. I'll go out and buy it Tuesday right now because now I'm curious to see if allergy and constant motion run on a 24 seven cycle is an effective means of nutrients export and parameter balance.
Skimmed those references and first not sure of their qualifications yet didn't see anything stating scientific proof macroalgae can't be lit 24/7 and need a dark period. That's solely my contention. Not challenging your knowledge but have you actually kept macroalgae or any plants lit 24/7 for extended periods? I'm speaking from actual experience and not citing others. FW plants and single cell algae were kept lit for a couple of years with no ill affects and growth was optimal to the needs of removing organics which was all I cared about facilitated by heavy feeding and zero measurable nutrients, stable pH and alkalinity.
Don't take my word for it. You have tinkered with running experiments what I gather therefore run a test where lights on day one and don't come off for six months and see what the results give you. Since my experiment with pom pom was only four months I can't speak to longer test although I'd think four months long enough to see ill affects.
Anecdotally, others have stated running chaeto and ATS 24/7 without ill affect.
My main purpose for Fuge/ATS being the removal of co2 with nutrient and metal control a side consideration. Goal is to run the lights off pH results and have the controller turn them off only if they exceed my maximum (yet to be determined) number. Was going to be 8.3 but now I'm curious if running 8.55 where higher increases calcium precipitation just to see how life responds.
Hear me out. I'm all for other's experience and science based testing yet no way even scientist can possibly test the affects on all life forms therefore when confronted with differing facts to my own experience then I choose my experience until further trials and tribulations tell me otherwise. Not saying I'm right and the only voice and simply expressing my thoughts and seeking knowledge. Why I asked "based on" because that might lead me in a new path.
As for a place on earth where plants receive 24/7 just consider the arctic winters where sun doesn't go away for months and plants there evolved to be lit 27/7 part of the year yet total darkness the other and although nature is a reference to how we keep any life in captivity the mere fact this is captivity means the boundaries set by nature may no longer exist.
Struggle to grasp how tumbling provides a dark period. Thought that was more to keep GHA from attaching and ensuring all sides get lit yet seen where myself with Hornwort and pom pom saw no issues with the underside not getting enough light and I don't tumble although trying to figure out how to get that accomplished since GHA beat my pom pom to literal death. Seen videos of think mats of chaeto grown in such a way as to prevent light from reaching the base and only the aquarist tumbling provided that and seen discussions where some don't bother and yet it grows. Skeptical but then perhaps further tests will enlighten me.
Last note, when first discovering pot growers and their 24/7 strategy I also searched the web for confirmation and failed to find any. Apparently science tells me they need darkness to perform certain functions and I doubt I had super plants in FW or salt therefore why I often question science as it can't possibly replicate everything we do and obtain conclusive evidence one must follow a strict path. Fact I didn't goes to prove you can't believe everything you read although the pot growers were correct. At least as to what they grow and my experiments.
One more last note. Unless running the Triton Method, life expectancy of Macroalgae is the next pruning therefore longterm affects of zero darkness need not be considered.