Is nutrient control an effective method of treating algae in a reef?

[mcarroll]

@rock_lobster awesome thread. I almost can't believe it hasn't diverged into algae pandemonium and nutrient chaos!

This seems to be contradictory to what many biologists say because cyanobacteria can fix dinitrogen (and in this way should be predominant when N-compounds are low) but it is my experience.

I still haven't satisfied my curiosity, so I could well be wrong in all this....

But when I tried to look up real info about the cyano we'd be likely to have in aquariums, it seems unlikely to me that we have any N-fixers....or at least an insignificant number of them on a system-wide basis. But "none" actually seemed likely from what I was able to find so far on N-fixing marine cyano.

What I also learned is that marine cyano more generally are very capable of using forms of dissolved phosphate that might be unavailable to other critters.

I presume they have excellent capabilities with respect to "unusable" nitrogenous molecules as well...not to mention natural affinities with the critters that do have those capabilities or which exude those molecules....seems like cyano will co-bloom with anything.

(Anyone know one or more cyano species that have been ID'd in aquariums?)

 

[rock_lobster]

Nitrates Still uncertain. My coral seem to do the best between 10-20ppm but havent noticed issues as high as 50ppm which is plenty high enough for any algae to thrive. Phos below .03 for extended periods and my coral have problems. I keep phos between .03-.1 ppm. Both of those parameters are also prime range for algae growth suggesting that there really isnt an effective nutrient control method to prevent algae but at the same time grow coral which would make sense considering that both coral and algae are found in the same environment. Targeting trace elements also would be pretty debatable considering coral and algae for the most part require the same trace elements and many of these are in such low concentrations that it would be difficult to make them a limiting factor for growth of algae but not coral.

 

[mcarroll]

Targeting trace elements also would be pretty debatable considering coral and algae for the most part require the same trace elements and many of these are in such low concentrations that it would be difficult to make them a limiting factor for growth of algae but not coral.

Nutrient limitation isn't all that simple since not all critters have equal capabilities at uptake of all elements or molecules.

"Unavailable" is all that matters, but it is not equivalent to "None."

Green algae, for example, are fantastic at P and N uptake....and can often even store massive reserves for when NONE is available in the water column.

Dinoflagellates are really terrible at uptake, by contrast, and must have little or no ability for storage.

(All makes sense given their differing lifestyles.)

So it's true that all life more or less shares the need for basic elements, but capabilities and extent of dependency vary....sometimes widely. So there may be room to target trace elements more than we do today.

@taricha has been working on this a little, in fact.

 

[Belgian Anthias]

live food! Those who are cultivating live food know how effective rotifer and pods consume algae. Introducing live cultures of phytoplankton and its basic consumers may be a good base for starting up and cycle a new mixed reef aquarium or/and to limit the growth of algae considered to be a nuisance.

 

[Randy Holmes-Farley Verified Community Expert]

Okey, I'm sure there is a certain ratio N : P that gives optimal growth for any organism using photosysntethesis. Probably different for all. But the question in this thread was if we in our aquariums can aviod "the bad algea" by having certain levels of nutrients(N and P in this case).
So what I wonder is why a special ratio will grow corals and not any algae.

Actually, I can't agree with the first sentence, and really do not see the rationale for thinking there is an optimal ratio (definitely disagree with that, it is obviously incorrect at either extreme of high or low values at the same ratio) or a pair of optimal concentrations (disagree, but less strongly).

On the second, less obvious point...If macroalgae is growing in that optimal ratio you suggest, and you add slightly more phosphate or nitrate (or ammonia), what bad thing would happen that this new ratio is not as optimal? You think growth will slow?

 

[Sallstrom]

Actually, I can't agree with the first sentence, and really do not see the rationale for thinking there is an optimal ratio (definitely disagree with that, it is obviously incorrect at either extreme of high or low values at the same ratio) or a pair of optimal concentrations (disagree, but less strongly).

On the second, less obvious point...If macroalgae is growing in that optimal ratio you suggest, and you add slightly more phosphate or nitrate (or ammonia), what bad thing would happen that this new ratio is not as optimal? You think growth will slow?

Randy, please try to understand even if English is not my first language I'm not the one believing there's a ratio N : P that will only allow corals and not algae to grow. I'm asking two people in that post you're citing, two people who have done claims. Please read my post again.

What I meant in the first sentence was: If you want to grow a monoculture(not a reef tank) you maybe could find a "best ratio" for the organism in that culture. I forgot to add levels of nutriets, sorry for that. Obviously there would be certain max and min levels of nutriets as well. But all that has almost nothing to do with the discussion in this thread.

The second question is no. Again, I'm not the one claiming that. Please read the post I cited.

If you want to find more thing to correct in my posts, check my grammar or spelling Just joking, but I find it strange that you picked my post and those things to disagree with, when I'm questioning the same thing as you. Hope we are okey

/ David

 

[Randy Holmes-Farley Verified Community Expert]

Randy, please try to understand even if English is not my first language I'm not the one believing there's a ratio N : P that will only allow corals and not algae to grow. I'm asking two people in that post you're citing, two people who have done claims. Please read my post again.

What I meant in the first sentence was: If you want to grow a monoculture(not a reef tank) you maybe could find a "best ratio" for the organism in that culture. I forgot to add levels of nutriets, sorry for that. Obviously there would be certain max and min levels of nutriets as well. But all that has almost nothing to do with the discussion in this thread.

The second question is no. Again, I'm not the one claiming that. Please read the post I cited.

If you want to find more thing to correct in my posts, check my grammar or spelling Just joking, but I find it strange that you picked my post and those things to disagree with, when I'm questioning the same thing. Hope we are okey

/ David

Fair enough. You just seemed to agree that there was a ratio for optimal growth, but I'm happy to direct my comments to anyone who thinks it.

This ratio idea keeps coming up over and over, and even if the original statement had merit, it gets repeated that ratios are the important factors, rather than the absolute concentrations themselves.

 

[brandon429]

Paul B:


all Ive ever asked of random web posters shy of them allowing me to remotely take apart their entire reef and put it back together with their dollars at risk was for one of them on a nice beach vacation to get out those salifert nitrate and po4 tests and run them. all declined

your picture of algae growth on a reef that grows sps made me remember that

I had me some Hawaii going friends too~just about begged for nitrate data taken from hobby kits not online scientific logs...was rather shocked that packing in more reef gear wasn't a highlight of their trip planning

it would be the neatest thread if Fiji goers, HI, Seychelles, canaries goers all these good places could get hobby kit nutrient readings so we can make inferences about how that ties into algae growth in tanks, or not. regarding nutrient control being an effective mode of algae control, ATS threads have data to support that it is

is it the ideal mode? I never ask about nutrient readings ever, at any time in our algae correction threads. neat dichotomy.

personally for me nutrients should be set exactly for what corals want, and algae is handled independently. just my fav way to avoid bleaching events/reactionary changes to plants that always seem to find a niche anyway when raspers are missing

 

[Randy Holmes-Farley Verified Community Expert]

The rules I run by:
a) make sure there are no macro algae in the system (bryopsis, bubble, etc) - if there is, treat with fluconazole first to eliminate the problem. You'll find that your phosphates will rise after being released by the macro algae die-off.
b) Now that you have free phosphate that can be used by the corals, feel free to keep it anywhere between 0.03 and 0.1.
c) live by the Redfield Ratio (NO3[ppm] / 65) / (PO4[ppm] / 95). You're aiming for 16. ..16 mol of NO3 to 1 mol of PO4.

As long as the ratio is right around 16, PO4 is at 2 or lower, levels of NO3 around 15 are fine and shouldn't cause algae issues. Here's a link to a chart for reference. Note that mg/l is the same as ppm (thank you, metric system!). There's simply no need to starve a reef tank when there's an optimal ratio between NO3 and PO4 that's been around 80 years and has proven itself out time and time again. You can find similar charts that give a little more leeway in the numbers, but the goal of all of them is to keep that ratio as close to 16:1 as possible. Do note that I'm not recommending you run your PO4 at 2. That can cause CaCO3 uptake issues with some corals. When reading the chart, please mentally convert the commas to decimal points (rest of the world vs. US notation).

http://www.dansreef.co.uk/wp-content/uploads/2018/01/RR.jpg

FWIW, you have personally put limitations on the values that the chart to you post does not, but IMO, the chart makes no sense, nor does the idea that a ratio is the important factor, rather than the actual values. This chart isn't even from a marine system. A while back I tracked down the original place it showed up (I think) and it was a planted freshwater aquarium discussion:

From an old post of mine:
FWIW, I found that table by image search, and I just do not think it is supplying info the way folks may interpret it.

This blog discusses it in the context of freshwater planted aquaria, where the goal is to provide optimal inorganic nutrients to keep the plants thriving, and when they are thriving, this author believes there is less chance for problem algae in competition with the plants.

http://www.aquascaping-blog.com/157/redfield-ratio

But, IMO, folks should not take away the idea that keeping a special balance of nutrient levels (especially when both are elevated) will reduce the chance for problem algae in a reef aquarium unless those nutrients are being used to drive a large amount of growth of something else, and that something else is outcompeting the problem algae for some other nutrient (such as iron, CO2, etc.).

 

[Paul B]

I had me some Hawaii going friends too~just about begged for nitrate data taken from hobby kits not online scientific logs...was rather shocked that packing in more reef gear wasn't a highlight of their trip planning

Brandon, I don't have any Salifert test kits or any other test kits. I think I may have a nitrate kit someplace in a wooden box packed with parchment. I will probably go back to the Caribbean in less than a year, so if anyone has a kit to lend me I may take it.

But I can tell you the salinity
Actually, I can't even do that. I took my swing arm hydrometer to Key Largo and drew a line on it. That is what I set my tank to, but my hydrometer is so far off I have no idea what my salinity really is. Key Largo is also not the best place to do that but whatever the salinity is there, my fish seem fine and my corals are growing a little too fast so it seems to work. I am sure most of that is luck, but who cares. I know most people are crazy about these numbers, but I am not.
I may be also to keep kissing gourmies or brine shrimp in there. It could be that far off.
If I think of it I will take it to the Caribbean or if I ever get back to the South Pacific.
I did test nitrate here in the Long Island Sound which is full of seaweed and it is zero.

 

[Belgian Anthias]

Why the focus is on nitrate and phosphate? And the redfield ratio? If one organism needs 1 and an other needs 10 x that amount, the redfield of these organisms will be 5.5.
Why not focus on something everybody wants but is limited available. Something on which specimen have developed a specific pathway in the competition to get it.
Why not, for example, focus on Iron? The competition for iron will limit the growth of cyano's, certainly in nitrogen limited conditions. If there is no competition for iron due to a low demand , maybe caused by limited nitrogen or phosphor availability causing limited general growth, cyano's may become the predominant specimen? May be!

 

[brandon429]

all the articles say the ocean reads just about that, a little higher than we like to keep. I recall from one of Randy's threads discussions over the years that .028s+ are known. calibration success indeed

mine gets that high agreed, neglect of topoff occurs. but its a slow workup, and correction too. I don't use refract its not worth the money for me, my swingarm is scratch marked as well.

 

[Randy Holmes-Farley Verified Community Expert]

Why the focus is on nitrate and phosphate? And the redfield ratio? If one organism needs 1 and an other needs 10 x that amount, the redfield of these organisms will be 5.5.
Why not focus on something everybody wants but is limited available. Something on which specimen have developed a specific pathway in the competition to get it.
Why not, for example, focus on Iron? The competition for iron will limit the growth of cyano's, certainly in nitrogen limited conditions. If there is no competition for iron due to a low demand , maybe caused by limited nitrogen or phosphor availability causing limited general growth, cyano's may become the predominant specimen? May be!

A number of us suspect iron (or perhaps another trace element) may be a limiting factor for algae (that is, why there is none) in some of the very nice SPS reefs with 1+ ppm phosphate and 100+ ppm nitrate.

 

[Jose Mayo]

What I would only say about nutrient testing in the aquarium is that they do not tell us what we have, but how much is left over ... any level of anything measured in tests is a sign that there was sufficient availability of this thing , to satisfy all the consumption needs of the creatures and still have something left.

What actually "controls" the aquarium is not what we measure but what we can not measure.

Regards

 

[mcarroll]

I think this article does a good job of illustrating why redfield isn't an ideal for us, but it can be used as a standard of sorts. (Not how we do.)

They measure the growth of chaeto under various N and P conditions and report on it's ratio along the way. Check it out.

Effect of nitrogen and phosphorus supply on growth, chlorophyll content and tissue composition of the macroalga Chaetomorpha linum (O.F. Mull), Kutz, in a Mediterranean Coastal Lagoon

 

[sprouseod]

I just saw a BRSTv episode that suggests it's the ratio of N to P that has an affect

 

[sprouseod]

10.5N to 1P

 

[rock_lobster]

A number of us suspect iron (or perhaps another trace element) may be a limiting factor for algae (that is, why there is none) in some of the very nice SPS reefs with 1+ ppm phosphate and 100+ ppm nitrate.

It could be but who knows. Coral do require basically the same elements as algae mainly because coral is made of a lot of algae zooxanthellae.

 

[Randy Holmes-Farley Verified Community Expert]

I just saw a BRSTv episode that suggests it's the ratio of N to P that has an affect

I'm not sure what they claimed, but again, it cannot make sense that the ratio alone is the thing to focus on.

Suppose that 0.03 ppm phosphate and 10 ppm nitrate is a good ratio for something.

Does that then mean the same ratio, at 0.00000000003 ppm phosphate and 0.00000000010 ppm nitrate is also going to be good? Or 300 ppm phosphate and 1,000 ppm nitrate?

All of those have the same ratio.

Seriously, I just don't get the whole ratio idea when used to discuss desirable levels. Why not just discuss the actual levels you think are desirable?

 

[rock_lobster]

I'm not sure what they claimed, but again, it cannot make sense that the ratio alone is the thing to focus on.

Suppose that 0.03 ppm phosphate and 10 ppm nitrate is a good ratio for something.

Does that then mean the same ratio, at 0.00000000003 ppm phosphate and 0.00000000010 ppm nitrate is also going to be good? Or 300 ppm phosphate and 1,000 ppm nitrate?

All of those have the same ratio.

Seriously, I just don't get the whole ratio idea when used to discuss desirable levels. Why not just discuss the actual levels you think are desirable?

That is true. I guess it could be relevant within certain limits but also not sure if the ratio is so important rather than just being over a certain threshold for growth.