Controlling phosphates with macroalgae.

[tmz]

I prefer a dark period 16 hours on. The N to P intake varies from species to species and to some extent is based on the levels in the water. 16: 1 is the the Redfield ratio, an enmasse measure of ocean phytoplankton which gave a ratio of 116 C(carbon); 16 N( nitrogen) to 1(phosphorus). Point is most of the food you are adding is likely close to that ratio ; so most algae should help reduce both phosphate and nitrogen proportionately.

 

[yacn]

I am running skimmer in sump. LFS told me to run light 24/7 and that they didn't need dark periods of time. He also mentioned it will help w/ my PH when my main tank lights go off at night

 

[tmz]

Whether algae needs a dark period or not is debateable; they get one in nature. 16 hours on including the lights off period works for me.

 

[outy]

Whether algae needs a dark period or not is debateable; they get one in nature. 16 hours on including the lights off period works for me.

Not only that the opposite cycle if the fuge is large enough, can offset the PH swing at night.


My problem with chaeto, is that it sucks up the Nitrate and phos out of the water quickly and after 3 weeks of rapid growth it then stops growing altogether.

Dosing iron now to see if I can kickstart it up again.

 

[bertoni]

Well, when I was talking to a scientist working at a company growing micro algae commercially, his opinion was that most algae likely could grow 24 hours a day if the light was not too intense. I don't know whether that's optimal, but it should be possible.

 

[jason2459]

I remember, maybe an article or some posts, back when I was growing macro in my refugium that it was recommended to give at least 4 hours of dark time for them to "breath" or something like that. Seemed to make since to me but I have no idea how accurate that is or even if it was right.

My ATS is on a 20 hour light schedule now and I know several people running their ATS 24hours. I'm going to try that out soon.

 

[bertoni]

I would leave a dark period, as well, although I would be more concerned with the various small animals that can grow in a refugium.

 

[jason2459]

I would leave a dark period, as well, although I would be more concerned with the various small animals that can grow in a refugium.

Now a days my sump is almost always completely dark minus a tiny bit of red glow coming from a drain pipe from my ATS. I bought it from Turbo Aquatics mainly because it's designed specifically to keep as much light in the ATS "box" where the screen is. My sump critters seem to like the almost eternal darkness better.

 

[rt67ghy]

Very interesting. Are you running a skimmer in your sump or is it all macro?

Thanks,

Mike

Yes, I'm running 2 undersize skimmers (because the height under my DT doesn't allow for one big one). I'm still getting a good amount of skimmate in both skimmers so I'm not planning to take those off-line soon. Also, I believe that the skimmers may take out some chemicals released by some corals which would otherwise harm my other corals if not taken care of. I'm not sure if macroalgae would remove all the harmful chemicals.

 

[rt67ghy]

Do algae need a dark period?

This is a very relevant question since it can affect macroalgae growth. I remember from my high school biology lessons that plants need a dark period for growth.

Trying not to get too technical, Light reactions need light to produce organic energy molecules (ATP and NADPH).

Dark reactions make use of these organic energy molecules (ATP and NADPH). This reaction cycle is also called Calvin Cycle. ATP provides the energy, while NADPH provides the electrons required to fix the CO2(carbon dioxide) into carbohydrates.

Although algae are not plants, the phosynthetic process in them is the same, so it appears that algae do need a dark period for building their cells.

I leave my ATS lights on 18 hours a day (Floyd in the threads on algae scrubbers recommends keeping the lights on for 18 hours). and my fuge lights on for 8 hours. I have found that the chaeto under my ATS lighting grows much better than the chaeto in my fuge which makes sense. I can always increase the photo period in my fuge depending on how much I want to reduce PO4 and how fast.

 

[bertoni]

As far as I can tell, they are called "dark reactions" because they can occur without light, not because they must happen in the dark. Lots of people run refugia with 24-hour light cycles and have at least reasonable growth. Searching for "Calvin Benson cycle" will turn up a lot of hits.

 

[rt67ghy]

Bertoni thanks for pointing this out. After I made the last post I realized that maybe the Calvin reaction happens in spite of the darkness and darkness is not actually a requirement for the reaction to take place. So, this means we can increase our algae growth if we choose to by keeping the lights on 24/7. I may try this as an experiment to see how much algae yield I get. Very interesting for those (like me) who have high nitrates and have been battling high PO4 for a year. Thanks again, I really appreciate it. To make further progress in this hobby, we need to get rid of misconceptions.

 

[bertoni]

You're welcome. Biology is very complicated. We all have more to learn.