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

[ddrueckh]

I think that a clean up crew is very important, but ridding a display of algae takes a two prong approach:

1) Clean up crew to eat the algae on the display rocks
2) Nutrient control to remove the nutrients released by the clean up crew

I have never had success with just nutrient control. I feel that the algae in the display (once it has taken hold) gets what it needs before whatever nutrient control one employs has a chance to do its job. I also believe that just using a clean up crew leads to a never ending cycle of the crew eating the algae but more growing because the nutrients remain in the tank. Yes, the clean up crew grows a little, but they poop a lot and release nutrients back into the tank.

Conclusion: Clean up crew to manually remove the algae from the rocks for us and nutrient control to remove the nutrients released. My favorite nutrient control is chaeto in a refugium. There are plenty of other ways...but that is my preferred method. Once you get things under control, I think that a small clean up crew is all that is needed to keep things balanced.

 

[a-mused]

Please explain why this ratio N/P will keep algae away. I don't see why algae shouldn't like the same water conditions as the corals(if the corals prefer that ratio is another question).

/ David

http://www.reefcentral.com/forums/showthread.php?t=2501551 .. post #4 explains why 16:1 is an optimal point. TL;DR: ratios higher than this have excess nitrates that will feed green algae while ratios lower than this will feed blue-green algae and cyano. At 16:1, zooxanthaelle (being an algae) will have an optimal N ratio for growth, with no excess N or P for nuisance algae to utilize.

 

[Lollipop]

I have argued this exact point for years. My system, in the main, is a big display, large refugium and frag tank. Not a wisp of algae in the display, some in the refugium, and it's a constant problem in the frag tank. Same water throughout the system, so nutrient levels in each tank are the same. What's the difference: herbivores. Lots of them in the display, a couple in the refugium and none in the frag tank. It's quite amusing to watch all the tangs, butterflyfish and angels crowd around a frag that I move out of the frag tank. Within an hour it is fully cleaned of any algae.

At the end of the day, though, I think it is neither one at the exclusion of the other..... it is both! You want to try to maintain low nutrient, but not NO nutrients; and you want the right balance of herbivores. It complicates things that some individual tangs, for example, decide they don't like algae versus others that do. My scopas, for example, eats no algae at all, ever. Mud brown lump of useless.

I am not an expert or anything. I barely keep corals alive at home. But my office tank is doing so well. There is no fish in the office as i dont go to the office often (2-4 times a week). A 5 gallon mixed, and there are 2 tiny snails and one blue leg hermit. When a frag or rock is covered with algae, i bring it to the office and it is clean next day. My difference is pods. i have tangs at home but they are not very through. Pods are! i think there are millions in the office tank as no one is eating them. i havent changed water for months! 10% water change, probably once 2-3 months! I feel bad to the snails and pods, i throw bits of a half algae tab in once a week. Corals get drops of liquids once a week. i think one day, pods will eat the hermit hungry. To me, it is the right balance between nutrition and cleaners.

 

[Hans-Werner]

Please explain why this ratio N/P will keep algae away. I don't see why algae shouldn't like the same water conditions as the corals(if the corals prefer that ratio is another question).

There is a very simple explanation why algae and corals don´t like the same conditions: Corals are more efficient in taking up nitrogen compounds than algae and benthic algae have access to phosphates deposited in rocks and gravel. But I think 16 : 1 is more the algal ratio, I would prefer 10 : 1 or even lower for hard corals. In coral reefs the nitrate : phosphate ratio usually is closer to 2 : 1.

 

[Paul B]

There is a very simple explanation why algae and corals don´t like the same conditions:

I don't know about this. On a dive last month I took this picture. This was where "The Coral Restoration Foundation" were growing and planting SPS corals on a reef. Algae all over the place but the corals seemed to be growing fine as were all the rest of the corals on that reef. I think most of this stuff is rumors which is why I like to document things in pictures.
Much of this information comes out of a lab somewhere and doesn't work in the real world.

 

[Luno]

My big 3

(1)HIGH IMPORT, HIGH EXPORT. It's the best style of reefing I have found to date. Keeps corals happy and nuisance problems to a minimum.

(2)REFUGIUM, if you don't want a nuisance algae the best way is to out compete it! Most people don't light a refugium enough to outcompete nuisance algae in the display.

(3)UV STERILIZER, it kills crap. You can argue they are not worth it blah blah blah. Everyone who ever has a bad word to say about using a uv in my experience has never actually used one.

 

[Hans-Werner]

I would prefer the corals only in our tanks without the algae. The water also doesn't look brilliant clear. Under higher nutrient conditions of course both can grow side by side, but you can manipulate your system. Why not doing it the right way?

 

[jwshiver]

(3)UV STERILIZER, it kills crap. You can argue they are not worth it blah blah blah. Everyone who ever has a bad word to say about using a uv in my experience has never actually used one.

I think there are two reasons people say UV sterilizers don't work. First they use an undersized UV and second they use too much flow. It is critical to get the proper flow through the UV. If done correctly they are a wonderful tool.

 

[Sallstrom]

http://www.reefcentral.com/forums/showthread.php?t=2501551 .. post #4 explains why 16:1 is an optimal point. TL;DR: ratios higher than this have excess nitrates that will feed green algae while ratios lower than this will feed blue-green algae and cyano. At 16:1, zooxanthaelle (being an algae) will have an optimal N ratio for growth, with no excess N or P for nuisance algae to utilize.

There is a very simple explanation why algae and corals don´t like the same conditions: Corals are more efficient in taking up nitrogen compounds than algae and benthic algae have access to phosphates deposited in rocks and gravel. But I think 16 : 1 is more the algal ratio, I would prefer 10 : 1 or even lower for hard corals. In coral reefs the nitrate : phosphate ratio usually is closer to 2 : 1.

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.

Corals and algae lives in the same ecosystem. Take away the herbivores from a coral reef and the algae will take over. I'm sure elevated levels of nutrients probably makes it even worse in the ocean, but IMO there have been so many aquariums showing that this is not the case in aquariums(even some tanks I take care of) that I don't believe a bit higher nutrients automatically will give you a problem with algae.

Her comes my opinion on algae in our tanks:
Algae, very often diatoms and other opportunistic algae, will grow if there is new and free space in a tank. That doesn't mean anything is wrong. These opportunistic algae will be grazed by herbivores. After some time other more hardy and slow growing algae and other organisms like sponges, will take over the space, and outcompete the opportunistic algae (if the conditions are kept stable). These sponges and coralline algae is wanted by most aquarists. On the reef these get eaten by urchins and other animals, leaving "clean" and light rocks.
What is IMO the big reasons why we see a lot of threads about algae is two things, not enough herbivores(or the wrong ones) and a lack of patience.

I know there are other ways to create great reef tanks other then mine So this is just my opinion. I don't like to treat a reef tank with medicine for example. And I don't think a UV-C is necessary most of the time. I'm aware of that I mostly work with larger tanks and that my ideas may not be good for nano tanks.

/ David

 

[Hans-Werner]

David, basically you are right but it is a bit more complicated in my eyes. Most of the phosphate a hard coral takes up is found in the skeleton and there in the organic matrix that initiates the skeletal formation. I am convinced that in calcifying algae like corallinaceans and Halimeda it is similar and they also have a higher phosphate demand because they are also calcifying organisms. What I want to say, corallinaceans and Halimeda indeed have the same needs and grow in the same tanks as scleractinians. At the same time I was able to keep that conditions so that the typical nuisance algae like Bryopsis and hair algae did not survive. This means they may have slightly different needs. I think nitrogen is the key. Keep nitrate low and phosphate detectable and the chances are better for good coral growth and few algal problems.

 

[Sallstrom]

David, basically you are right but it is a bit more complicated in my eyes. Most of the phosphate a hard coral takes up is found in the skeleton and there in the organic matrix that initiates the skeletal formation. I am convinced that in calcifying algae like corallinaceans and Halimeda it is similar and they also have a higher phosphate demand because they are also calcifying organisms. What I want to say, corallinaceans and Halimeda indeed have the same needs and grow in the same tanks as scleractinians. At the same time I was able to keep that conditions so that the typical nuisance algae like Bryopsis and hair algae did not survive. This means they may have slightly different needs. I think nitrogen is the key. Keep nitrate low and phosphate detectable and the chances are better for good coral growth and few algal problems.

I understand and I agree on that what you wrote could have happened. But it could also have been that something outcompeted these nuisance algae because you kept the water parameters stable during a long period?

And I agree that everything is more complexe. But I like to keep it as simple as possible. And I've tried low N several times in different reef tanks at work, and sometimes everything looks great, and sometimes we start to get cyanobacteria. Specially in smaller tank(frag tanks connected to a larger systems for example) there have been cyano problems, even if the display tank were fine. I know we have had this discussion before and have different experiences, thats fine.
Anyway, an easy way to stay on "the safe side" is to keep detecteble N and P and have a good clean up crew. Then you don't need to keep an exact level of nutrients(which is hard to meassure anyway, how accurat is our NO3 hobby tests?).

/ David

 

[Paul B]

I think there are two reasons people say UV sterilizers don't work. First they use an undersized UV and second they use too much flow. It is critical to get the proper flow through the UV. If done correctly they are a wonderful tool.

I know they work, I just think they work too well to destroy things I want to keep in my water which is also crystal clear. But I also have some 16" sponges in there that filter most suspended things out which to me anyway, is a more natural method and it utilizes the micro life forms in the water rather than destroy them. The tiny life becomes growing sponge and I harvest the sponges that grow very fast.

Like this one over a sunken ship that my Grand Son gave me so I have to put it in the tank before he comes over.

 

[ca1ore]

I am not an expert or anything. I barely keep corals alive at home. But my office tank is doing so well. There is no fish in the office as i dont go to the office often (2-4 times a week). A 5 gallon mixed, and there are 2 tiny snails and one blue leg hermit. When a frag or rock is covered with algae, i bring it to the office and it is clean next day. My difference is pods. i have tangs at home but they are not very through. Pods are! i think there are millions in the office tank as no one is eating them. i havent changed water for months! 10% water change, probably once 2-3 months! I feel bad to the snails and pods, i throw bits of a half algae tab in once a week. Corals get drops of liquids once a week. i think one day, pods will eat the hermit hungry. To me, it is the right balance between nutrition and cleaners.

Although I used fish as my herbivore example, it's quite correct that there are inverts that consume algae as well (I would absolutely include pods in the broader definition of a clean-up-crew). Whether your example is a consequence of pods eating the algae or there is some element for algae growth missing in your office tank is unknown. Your conclusion about the pods is not unreasonable, but correlation is not always causation.

 

[ca1ore]

Everyone who ever has a bad word to say about using a uv in my experience has never actually used one.

I don't think that is even remotely true. OK, yes, views do get parroted by novice reefers without direct experience, but there are plenty of long-timers that have used UV and concluded it is not worth the cost and effort. I don't personally happen to agree, and I do run an oversized unit on my system at flow levels that are intended for parasite reduction; but I also have reasonable expectations for what it will and won't do.

 

[Camaro Show Corals]

alage scrubber will help

 

[Hans-Werner]

I understand and I agree on that what you wrote could have happened. But it could also have been that something outcompeted these nuisance algae because you kept the water parameters stable during a long period?

I agree, it is even more complicated. Good growing scleractinians incorporate also a lot of iron. In this way coral growth could also make life difficult for many algae. But what is important is that especially SPS need some phosphate for good growth, the lower the phosphate concentration the slower SPS growth the less competition.

In my experience it is low phosphate that causes cyanobacterial growth. I had cyanobacterial growth even with 15 or 20 ppm nitrate and low phosphate concentrations. In my experience very low or fluctuating phosphate concentrations cause cyanobacteria. 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.

 

[Belgian Anthias]

That is of course also true, but the majority of fish posts seem to hone in on nitrates and phosphates. There is very little mentioning of iron, magnesium, silicon, calcium, potassium, sulfur or any trace elements like copper, zinc, cobalt or molybdenum and we don't normally test for them.

In nature the levels are very low but the supply is unlimited. Creating shortness ends up in eliminating competitors, supports pests and explosive outbreaks when nutrients and building materials become available.

End the 60 'ties and begin the 70'ties we could not test for nitrates and phosphate. Water changes where made based on pH en de period between two pH corrections; When the pH stayed only stable for a short time it was assumed that nitrification had effected the buffering capacity to much and nitrates where high ( between 200 and 300 ppm!). Expensive water changes where postponed as long as possible. That time having green algae in the seawater aquarium was considered as good housekeeping and an indication for a healthy aquarium. Dyscallus where spawning on a regular base in these high nitrate conditions. Even in these high nutrient conditions we where never confronted with outbreaks of cyano's or hair algae although I have seen other aquaria in which they could not be controlled.
High nitrates and phosphates are not the triggers for explosive algae growth as growth may be mainly controlled due to the competition for the other building materials and by growth limiting toxines produced by the specimen and its competitors.

 

[hart24601]

It's always interesting how systems we have can be so very different. I have only set up 4 or 5 tanks over the years plus helping friends set up their tanks and the differences between systems (along with issues) still surprises me. I set up a tank not long ago, pretty much problem free, sps right after initial cycle. Needed to be dialed in, but no real issues. Helped friend set up a system a bit larger, but using same rocks (same order) similar equipment all that jazz... dino nightmare. Feeding close to the same, no major differences. Other tanks I have had same sort of thing, some are pretty issue free, others algae nightmare. My old 120 I ran at 0ppb phosphate constantly, best reef I ever had. Nutrient control totally worked for that tank. Other systems clean up crews were needed.

Basically I don't think we should have a ridged approach in the hobby. We have a tendency to look at what has worked for us, especially if we have had success with 1 or 2 systems, and develop cognitive bias. Our tank may have been going for 10 years plus but that doesn't mean particular solutions will be effective for everyone. In fact the more our systems deviate from others, be it age, stocking levels, coral size many times the less applicable our current experiences will be for people starting out or that have particular issues.

 

[Paul B]

High nitrates and phosphates are not the triggers for explosive algae growth as growth may be mainly controlled due to the competition for the other building materials and by growth limiting toxines produced by the specimen and its competitors.

This is true. And why I always question answers that recommend to limit these two chemicals and your problems will be solved. My reef has been going through cycles since the 70s where I could open up a produce stand or have absolutely no algae. I don't personally care about algae because I have spent almost 300 hours underwater so I know it grows on all healthy reefs, but I, like everyone else don't want it covering my corals. I just force it to grow on an algae scrubber, that way I don't have to care what causes or promotes it. When the scrubber needs cleaning, I know it removed the algae along with the nutrients and all is well. It doesn't grow in my reef itself.

 

[Lollipop]

Although I used fish as my herbivore example, it's quite correct that there are inverts that consume algae as well (I would absolutely include pods in the broader definition of a clean-up-crew). Whether your example is a consequence of pods eating the algae or there is some element for algae growth missing in your office tank is unknown. Your conclusion about the pods is not unreasonable, but correlation is not always causation.

The tank struggled with lots of problems including hair algae from the beginning primarily due to small size and no sump. Water movement was never enough the space in the AIO sump was too small to upgrade the pump. It’s fluval evo 5. When I gave up all those effort to filter nutrient and remove phosphate etc, algae started disappear. Pods were populating. I now have nothing but a tiny skimmer. Algae still appear on glass after feeding corals. I clean the glass and then probably the scraps eaten by pods. So it’s not algae not developing. It’s there but eaten soon.