Nano Macroalgea Tank

[crusso1993]

Its a family farm, have been moving back and forth from the city before but decided to make it more permanent this year. Thats why I moved my tanks here. You can look it up in IG, youtube and google as "Finca Dracula". I joke that I have experience with mountain reefs because some of the branches have moss and lichen that look like corals.
I actually started this project because I saw pictures of coldwater planted tanks, and they seemed so otherworldly that it inspired me to make a marine garden

Just followed you on IG. Wow! Amazing and beautiful surroundings not to mention your photography skills.

 

[Andy Macro]

Just followed you on IG. Wow! Amazing and beautiful surroundings not to mention your photography skills.

Thanks, it is a gorgeous place! Can't take the credit for all the photos, we've got a photographer here who is great at this

 

[Lasse]

I´m interested of knowing some parameters - not because I´m setting up a macro by myself but we are going to set up a huge (10 000 l) cold water macro tank (swedish fauna) in a year or two.

ph - if possible during 24 hours and your alkalinity (KH) - especially interested if the photosynthesis consume alkalinity in higher pH. Do you ad CO2?

Sincerely Lasse

 

[Andy Macro]

Wow, my inspiration to start this was a cold water macroalgea aquarium I saw online, and I wish one day I could get a hold to some of those species, since where we are the water stays that temperature year round and id be easier to maintain.
I am also learning to make a macroalgea aquarium with those dimensions for my botanical garden.

Regarding your questions:

• Im very new at this so am still finding out everything, specially since there is very little information out there.
• Haven't witnessed any pH swings yet
• I didn't control for calcium and alkalinity since most people advised me it was not necesary but later I've been more in touch with people that grow macroalgea aquariums and all are compensating for it. I did notice that water changes induced growth and I think it is mainly because of the alkalinity brought by the new water. Since we are in Coronavirus lockdown I cant get a KH meter or 2 parts so im depending on 4% water changes every other day and 16% once a week, just started but the results seem to be good.
• I've wondered the same for CO2 and am curious myself. I am thinking of setting up a smaller tank to test this and see if its possible to add a CO2 diffuninator without affecting much the pH of the water and dissolving all the calcium organisms. Also curious if Calcium reactors can provide this CO2. I read that aquatic plants can't use carbonic acid for photosynthesis but haven't found if this is also the case with Macros
• What I did find was that green light spectrum seems to have stimulated growth in red macros and also that bright light seems to burn many of them.
• Am still figuring out fertilization. Am curently supplementing:
  0.07 ppm nitrate, .04 ppm ammonium, .009 ppmphosphorous and .03 ppm iron every other day trying to simulate levels in the oceans.
• skimmer runs only at night, don't know if its adding CO2 to the water but it seems to be helping

 

[Lasse]

In a theoretical perspective - it should be a consumption of alkalinity (KH) if you run the tank in pH that is normal in marine tanks because of lack of CO2. The macros take up CO2 from the water - pH rise - lesser CO2 can enter the water. The macros start to produce their own CO2 from the HCO3 and CO3 ions in the water (the alkalinity depends on these ions). The alkalinity get lower and lower. However this is not the same process as the calcification process and mostly only alkalinity will be consumed - not calcium.

Green light is of huge importance IMO (even if we not believe in this in reefing community). It is not so effective in photosynthesis but it can penetrate through living materia and therefore generate photosynthesis even if blue and red is absent. Take a walk out in the jungle around you - even below the densest tree canopy you can see green things - it means that green photons going through the canopy and can be reflected/used in some photosynthesis lower down. Red and blue things - does not have the same colour below a dense canopy. The red and blue photons is already catched of the canopy and can´t be reflected or be used in photosynthesis!

Sincerely Lasse

 

[Andy Macro]

In a theoretical perspective - it should be a consumption of alkalinity (KH) if you run the tank in pH that is normal in marine tanks because of lack of CO2. The macros take up CO2 from the water - pH rise - lesser CO2 can enter the water. The macros start to produce their own CO2 from the HCO3 and CO3 ions in the water (the alkalinity depends on these ions). The alkalinity get lower and lower. However this is not the same process as the calcification process and mostly only alkalinity will be consumed - not calcium.

Green light is of huge importance IMO (even if we not believe in this in reefing community). It is not so effective in photosynthesis but it can penetrate through living materia and therefore generate photosynthesis even if blue and red is absent. Take a walk out in the jungle around you - even below the densest tree canopy you can see green things - it means that green photons going through the canopy and can be reflected/used in some photosynthesis lower down. Red and blue things - does not have the same colour below a dense canopy. The red and blue photons is already catched of the canopy and can´t be reflected or be used in photosynthesis!

Sincerely Lasse

Interesting, so adding CO2 during the day would stop them from needing to consume HCO3. I would then setup a small testing aquarium for this. Probably monitor pH and alkalinity at different bubbles per second. Shouldn't be hard.
Regarding light green light reaches up to 30 meters bellow sea surface and phycoerythrin, an important pigment absorbs green spectrum. I do think it offers photosynthetic activity similarly to how It induces Red coloring in freshwater planted tanks.

 

[Lasse]

Yes - CO2 in the day is an option - but watch your pH. Should not be lower than 8 IMO.

According to skimmer

A skimmer will lower the O2 concentration and rise the CO2 throughput during photosynthesis and lower the CO2 concentration and rise the O2 throughput during no photosynthesis. IMO - the ideal should be to run the skimmer during photosynthesis and not run it during no photosynthesis. The problem with this is that a dense biomass give a high respiration that could totally deplete the oxygen level during early morning hours. It is a well known situation in dense populated freshwater tanks (high biomass of plants)

According green light - see this thread

For Advanced Hobbyists - Importance of Green Light in Photosynthesis

Shawn Wilson (lighting expert in Canada) forwarded this journal reference to me. https://academic.oup.com/pcp/article/50/4/684/1908367 In a nutshell, green light can promote photosynthesis better than red light in conditions of intense white light. Although the research is directed at...

www.reef2reef.com

and this especially this experiment in the thread

Sincerely Lasse

 

[Andy Macro]

Yes - CO2 in the day is an option - but watch your pH. Should not be lower than 8 IMO.

According to skimmer

A skimmer will lower the O2 concentration and rise the CO2 throughput during photosynthesis and lower the CO2 concentration and rise the O2 throughput during no photosynthesis. IMO - the ideal should be to run the skimmer during photosynthesis and not run it during no photosynthesis. The problem with this is that a dense biomass give a high respiration that could totally deplete the oxygen level during early morning hours. It is a well known situation in dense populated freshwater tanks (high biomass of plants)

According green light - see this thread

For Advanced Hobbyists - Importance of Green Light in Photosynthesis

Shawn Wilson (lighting expert in Canada) forwarded this journal reference to me. https://academic.oup.com/pcp/article/50/4/684/1908367 In a nutshell, green light can promote photosynthesis better than red light in conditions of intense white light. Although the research is directed at...

www.reef2reef.com

and this especially this experiment in the thread

Sincerely Lasse

Makes sense. So Im looking at the pH-Alk-CO2 chart and it would seem that the goal would be to keep pH at 8, Alk between 10-12 so that CO2 concentration would be around 3.5 ppm. I could setup an experiment once Covid crisis is over where I could have 3 tanks, one with CO2 and Macros, one with Macros, and one with only CO2 and check how Alkalinity, pH and plant weight changes over a couple of weeks. It should answer some questions. Do you know if anyone has tried this or something similar?

I know that with light passing through leaves it changes the amount of red vs deep red spectrum and plants measure that difference to know if there is a plant above them. Woudnt be surprised if green light is used as well. It makes sense that some plants on low light conditions would addapt to absorb more of the green spectrum if its more available under the canopy. With regards to red Macros I suspect that since look red they are absorbing more of the blue-green spectrum so a blue-green supplement to light should benefit them.

 

[Andy Macro]

Here are some new pictures. I added one of the tank so you can get an idea of how it is and one artistic with the bubbles from the skimmer.

 

[Andy Macro]

ph - if possible during 24 hours and your alkalinity (KH) - especially interested if the photosynthesis consume alkalinity in higher pH. Do you ad CO2?

Sincerely Lasse

Just got the KH test and the tank tested 9 KH, which is 3 points lower than the control water. Will start raising it back to 12.

 

[Randy Holmes-Farley Verified Community Expert]

Very nice tank!

Just got the KH test and the tank tested 9 KH, which is 3 points lower than the control water. Will start raising it back to 12.

Photosynthesis isn't consuming alkalinity (where would it go?) but either coralline algae or abiotic precipitation of calcium carbonate (or rising nitrate, but that seems unlikely in this case) will deplete alkalinity.

 

[Andy Macro]

Photosynthesis isn't consuming alkalinity (where would it go?) but either coralline algae or abiotic precipitation of calcium carbonate (or rising nitrate, but that seems unlikely in this case) will deplete alkalinity.

Thanks,
At first I though so too but after advise from people with experience in macros, it turns out that they all report a drop in alkalinity from the macros and supplement frequently. Then I did some research and I came across an article talking about how plants in high alkalinity waters depend on carbonate as a carbon source because it is more available than CO2.

@Lasse suggests that with a CO2 supplementation Alkalinity should remain stable as they would not need to consume carbonate. It should be easy to test once I get a chance to setup multiple small test tanks.

 

[SMSREEF]

Here are some new pictures. I added one of the tank so you can get an idea of how it is and one artistic with the bubbles from the skimmer.

You have an absolutely stunning tank Andy!

 

[Lasse]

Very nice tank!

Photosynthesis isn't consuming alkalinity (where would it go?) but either coralline algae or abiotic precipitation of calcium carbonate (or rising nitrate, but that seems unlikely in this case) will deplete alkalinity.

I´m with you if it is CO2 that is consumed in a direct way. The C that will be lost from the carbonate system (into biomass) will be replaced by C from the airs CO2 that will be forced down into the water because of the pH rise the uptake of waters CO2 will cause. The interface air/water will make it to zero-sum game.

On the other end - if they should use CO3 and convert that into CO2 we should - IMO - have a acidification process in the water and production of oxygen radicals and/or oxygen gas. The acidification because the it will need one HCO3 ion to be converted into a CO3 ion for each CO3 ion the process use. The acidification will lead to the CO2 level increase in the water and you will lose this C either to the photosynthesis or the air/water interface (depending on the actual pH and air content) IMO - if such a process exist ( all sources I have say no - it not exist) it should be consuming C from the carbonate systems in both ends of the system - still IMO - very much IMO. Compare the nitrification process that use CO3 as first step in production of organic C. That process is consuming alkalinity.

What´s happen with if they use HCO3 as main source (it has been shown that high alkalinity both freshwater and marine plants/algae has an ability to do that) The HCO3 has to be converted to one CO2 molecule, one H ion and one O atom. Either external or/and internal, either enzymatic or/and through pH shift between different cell layers. Interesting is what happens with the lose H ions and O radicals. If all of them form OH ions/radicals - I´m with you - this process is alkalinity neutral as the use of pure CO2. But if not all O radicals will find a H ion and either do its job as an O radical (oxidise something else) or find another O and become O2 gas - the C balance in the carbonate buffering system will not be even. the photosynthesis process will consume C from the carbonate buffering system

I have no evidences at all to what I´m suggesting more than two things I have seen / heard regarding photosynthesis in water with high alkalinity and organisms with known ability to use HCO3 as a starting point for photosynthesis.

1. The pH swing in these system is not as high as it is in water with low/no alkalinity at all. Some of these effects can be is related to the buffering ability - but can all?
2. I have seen and heard of other with marine or high alkalinity fresh water plants that there is a consumption of alkalinity in such systems equal with what Andy Macro report

Sincerely Lasse

 

[Randy Holmes-Farley Verified Community Expert]

Thanks,
At first I though so too but after advise from people with experience in macros, it turns out that they all report a drop in alkalinity from the macros and supplement frequently. Then I did some research and I came across an article talking about how plants in high alkalinity waters depend on carbonate as a carbon source because it is more available than CO2.

@Lasse suggests that with a CO2 supplementation Alkalinity should remain stable as they would not need to consume carbonate. It should be easy to test once I get a chance to setup multiple small test tanks.

I recognize that many use bicarbonate, but unless they are calcifying macroalgae such as halimeda, they cannot consume alkalinity. I discuss this in great detail in this article:

Photosynthesis and the Reef Aquarium, Part I: Carbon Sources by Randy Holmes-Farley - Reefkeeping.com

http://reefkeeping.com/issues/2006-10/rhf/index.php

The process of photosynthesis cannot consume alkalinity (I won't get into the chemistry details, but to get rid of alkalinity would mean getting rid of negative charges, photosynthesis is a net charge neutral process). Something else is using it.

 

[Randy Holmes-Farley Verified Community Expert]

I´m with you if it is CO2 that is consumed in a direct way. The C that will be lost from the carbonate system (into biomass) will be replaced by C from the airs CO2 that will be forced down into the water because of the pH rise the uptake of waters CO2 will cause. The interface air/water will make it to zero-sum game.

On the other end - if they should use CO3 and convert that into CO2 we should - IMO - have a acidification process in the water and production of oxygen radicals and/or oxygen gas. The acidification because the it will need one HCO3 ion to be converted into a CO3 ion for each CO3 ion the process use. The acidification will lead to the CO2 level increase in the water and you will lose this C either to the photosynthesis or the air/water interface (depending on the actual pH and air content) IMO - if such a process exist ( all sources I have say no - it not exist) it should be consuming C from the carbonate systems in both ends of the system - still IMO - very much IMO. Compare the nitrification process that use CO3 as first step in production of organic C. That process is consuming alkalinity.

What´s happen with if they use HCO3 as main source (it has been shown that high alkalinity both freshwater and marine plants/algae has an ability to do that) The HCO3 has to be converted to one CO2 molecule, one H ion and one O atom. Either external or/and internal, either enzymatic or/and through pH shift between different cell layers. Interesting is what happens with the lose H ions and O radicals. If all of them form OH ions/radicals - I´m with you - this process is alkalinity neutral as the use of pure CO2. But if not all O radicals will find a H ion and either do its job as an O radical (oxidise something else) or find another O and become O2 gas - the C balance in the carbonate buffering system will not be even. the photosynthesis process will consume C from the carbonate buffering system

I have no evidences at all to what I´m suggesting more than two things I have seen / heard regarding photosynthesis in water with high alkalinity and organisms with known ability to use HCO3 as a starting point for photosynthesis.

1. The pH swing in these system is not as high as it is in water with low/no alkalinity at all. Some of these effects can be is related to the buffering ability - but can all?
2. I have seen and heard of other with marine or high alkalinity fresh water plants that there is a consumption of alkalinity in such systems equal with what Andy Macro report

Sincerely Lasse

No. If you use bicarbonate or carbonate to make CO2 internally, you MUST release OH-. That maintains the external alkalinity unchanged:

HCO3- + H2O ---> H2CO3 + OH- ---> H2O + CO2 + OH-


There are lots of highly oxidizing species formed during photosynthesis, including H2O2, superoxide radical (O₂-), and singlet oxygen (¹O₂). None of these permanently deplete alkalinity, either as is, or after decomposition, in any way that I can see.

 

[Randy Holmes-Farley Verified Community Expert]

There are lots of ways that alkalinity can actually be depleted in small amounts. It goes unnoticed in reef tanks where corals and coralline algae are big users, but one need not look to hypothetical uses of alkalinity in noncalcifying macroalgae to see a lot of ways alkalinity can be depleted in a macroalgae aquarium. All calcifying organisms will consume it. These include:

1. Snails
2. Coccolithophores (tiny calcifying algae; these may be the biggest user of alkalinity in the world's oceans)
3. Echinoderms: sea stars, sea urchins, sand dollars, crinoids, sea cucumbers and brittle stars
4. Crustaceans such as crabs and lobsters
5. Foraminifera (tiny calcifying organisms)
6. Shelled molluscs
7. Many soft corals
8. Tube worms
9. Some amphipods

 

[Andy Macro]

I recognize that many use bicarbonate, but unless they are calcifying macroalgae such as halimeda, they cannot consume alkalinity. I discuss this in great detail in this article:

Photosynthesis and the Reef Aquarium, Part I: Carbon Sources by Randy Holmes-Farley - Reefkeeping.com

http://reefkeeping.com/issues/2006-10/rhf/index.php

The process of photosynthesis cannot consume alkalinity (I won't get into the chemistry details, but to get rid of alkalinity would mean getting rid of negative charges, photosynthesis is a net charge neutral process). Something else is using it.

Yes, the carbonate and bicarbonate woud not be used directly in photosynthesis but would have to be converted to CO2 first. Macroalgeas have transport pores to absorb HCO3− and then would induce localized acidic conditions in the apoplast to convert the HCO3− to CO2 which in turn is used in photosynthesis. This would resultind OH- would have to be expelled to the water to maintain the local pH. Since this reaction does not change the total number of ions there is no need to remove negative ions and does result in a decreased alkalinity while (IMO) increasing the pH (need to test this).

Thanks for the link, it helped a lot understanding the chemistry.

 

[Andy Macro]

I´m with you if it is CO2 that is consumed in a direct way. The C that will be lost from the carbonate system (into biomass) will be replaced by C from the airs CO2 that will be forced down into the water because of the pH rise the uptake of waters CO2 will cause. The interface air/water will make it to zero-sum game.

On the other end - if they should use CO3 and convert that into CO2 we should - IMO - have a acidification process in the water and production of oxygen radicals and/or oxygen gas. The acidification because the it will need one HCO3 ion to be converted into a CO3 ion for each CO3 ion the process use. The acidification will lead to the CO2 level increase in the water and you will lose this C either to the photosynthesis or the air/water interface (depending on the actual pH and air content) IMO - if such a process exist ( all sources I have say no - it not exist) it should be consuming C from the carbonate systems in both ends of the system - still IMO - very much IMO. Compare the nitrification process that use CO3 as first step in production of organic C. That process is consuming alkalinity.

What´s happen with if they use HCO3 as main source (it has been shown that high alkalinity both freshwater and marine plants/algae has an ability to do that) The HCO3 has to be converted to one CO2 molecule, one H ion and one O atom. Either external or/and internal, either enzymatic or/and through pH shift between different cell layers. Interesting is what happens with the lose H ions and O radicals. If all of them form OH ions/radicals - I´m with you - this process is alkalinity neutral as the use of pure CO2. But if not all O radicals will find a H ion and either do its job as an O radical (oxidise something else) or find another O and become O2 gas - the C balance in the carbonate buffering system will not be even. the photosynthesis process will consume C from the carbonate buffering system

I have no evidences at all to what I´m suggesting more than two things I have seen / heard regarding photosynthesis in water with high alkalinity and organisms with known ability to use HCO3 as a starting point for photosynthesis.

1. The pH swing in these system is not as high as it is in water with low/no alkalinity at all. Some of these effects can be is related to the buffering ability - but can all?
2. I have seen and heard of other with marine or high alkalinity fresh water plants that there is a consumption of alkalinity in such systems equal with what Andy Macro report

Sincerely Lasse

I found this article that explains the mechanism: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5983714/

It basically says that the acidification to turn HCO3− to CO2 happens in the apoplast through active localized acidification. Which goes along with what you are saying. The resulting excess OH- would have to be expelled to the water to maintain the pH inside the cells.

The resulting release of OH- would predict an increase in pH and reduction in buffering capacity of the tankwater instead of a decrease. Wouldn't you think?

I am guessing that those H and O radicals don't do much damage since they would occur briefly in the apoplast which is a region without much metabolic activity.

 

[Andy Macro]

There are lots of ways that alkalinity can actually be depleted in small amounts. It goes unnoticed in reef tanks where corals and coralline algae are big users, but one need not look to hypothetical uses of alkalinity in noncalcifying macroalgae to see a lot of ways alkalinity can be depleted in a macroalgae aquarium. All calcifying organisms will consume it. These include:

1. Snails
2. Coccolithophores (tiny calcifying algae; these may be the biggest user of alkalinity in the world's oceans)
3. Echinoderms: sea stars, sea urchins, sand dollars, crinoids, sea cucumbers and brittle stars
4. Crustaceans such as crabs and lobsters
5. Foraminifera (tiny calcifying organisms)
6. Shelled molluscs
7. Many soft corals
8. Tube worms
9. Some amphipods

They probably are consuming but if you look at my tank, but I dont have many of those: few small tube worms, amphipods, not much coraline action and very small soft coral. While the drop is happening at ~1 dKH/day