One more reason to avoid Caulerpa.

[piercho]

Just because Eric is so fond of the Caulerpa algae:
Nitrogen- versus phosphorous-limited growth and sources of nutrients for coral reef macroalgae. S.T. Larned, Marine Biology (1998) 132: 409-421

C. racemosa had a dry weight N:P composition of 150:1. C. sertularioides, 200:1 (Table 2). WOW!! Some plants (Codium, Sargassum, and others) grew better in an elevated P environment. Both Caulerpas showed retarded growth in an elevated P environment, and elevated P slowed their growth more than any of the other studied plants (Fig 2).

It doesn't look to me that Caulerpa is the best choice of plant for export if getting rid of P and promoting reasonable N:P ratios in the tank water is the goal. I'd further speculate that using Caulerpa as a main source of export could set up conditions where P becomes excessive, limiting the Caulerpa, and causing N-fixing Cyanobacters to kick into full throttle.

Anybody have any thoughts?

[G-money]

Skim your tank heavily and wet and you will likely vastly outperform any and all methods of export aside from very large water changes and major biomass removal on several levels.

None of the macros are that good at phosphate uptake from what I understand - not relatively. Cyanobacteria and microalgae are much more effective, which is one reason you can still have nasty problems with them even though your sump or refugium is full of Caulerpa... I put the ixnay on Caulerpa about 6 months ago and will never use it in a reef tank again.

[Dag]

My caulerpa stopped growing in the fuge. You're saying this is because of high phospate? and if so, what's the bad thing it's doing to my tank?

[G-money]

Dag,

It could be a number of things - it may be entering a sexual cycle, but low nutrients is probably the limiter in most situations. I have had a couple handfuls of Chaeto in my sump for months and it hasn't grown at all. I have a large Beckett skimmer though and I run it wet. There's just nothing left for the algae...I bet I'd see it grow if I shut my skimmer off for several hours a day, but why would I do that?

Caulerpa sp. releases different kinds of organics - caulerpin is one, but there are others. Organic buildup in general is bad for corals - I have been told it is one possible cause of STN (slow tissue necrosis). If you have a good skimmer, change water somewhat frequently, and/or effectively use carbon, the effects of this and any other organic will be mitigated to some degree.

[reefhorse]

piercho,
I do not think the relative dry weights of macroalgae has any relevance to effectriveness to phosphate removal. The real measue is how much phophate a caulerpa species will extract for the aquarium. In Eric's latest book the amount of phosphate removal is awesome. If you have a phospate problem you will see a microalgae bloom if you have excess nitrogen or a cyano bloom if you do not have excess nitrogen. If you do not them the caulerpa is doing its job. The phosphate that is doing the damage is the organic phosphate (heavy efficient skimming will eliminate this) not the iorganic phosphate. The phosphate test measure the inoranic phosphate as do the phosphate removal hydroxides. Water changes increase your phosphate load as phosphate is present in RO water. I have both skimmer and skimmerless systems and have never had a cyano bloom following the cycling period. I attribute this to the caulerpa in the refugiums.
Sncerely,
John

[G-money]

I dunno...there shouldn't be any appreciable organic phosphate in the water. RO or RODI.

DI should remove any free phosphate. If present, it's so infintesimally small it's irrelevant. A TDS meter will tell the tale...

Organic phosphate is assimilated so quickly anyaway that any trace amounts should theoretically be taken up by bacteria as your mixing container is filling over the course of however many hours...I know I have a nice thin slimy coating on my mixing container after a day or two of mixing. I would assume it's all bacteria.

[piercho]

My caulerpa stopped growing in the fuge. You're saying this is because of high phospate?

I'm suggesting that it could have become N-limited, and that the N:P ratio could have been driven to a low ratio due to it's growth requirements. Not that your PO4 is currently high, even though I see where you would have taken my statement that way.

I'd further speculate that using Caulerpa as a main source of export could set up conditions where P becomes excessive, limiting the Caulerpa, and causing N-fixing Cyanobacters to kick into full throttle.

A better statement would have been "could set up conditions where N:P is low, leading to a shift in plant production to P-limited plants like certain specie of blue-greens."

If your Caulerpa's rate of growth has slowed dramatically, and nothing else (flow, light, water and food inputs) has changed, it would seem that it has become nutrient limited. N and P are major nutrients, but minor nutrients like Fe can also inhibit growth. At any rate, if your Caulerpa is comparable to the ones in Larned's study, it seems unlikely that it is being P-limited.

[EricHugo]

I think an important aspect of this topic is the nature of Caulerpa to trap sediments and extract using rhizomes. That's why it grows so well on the enriched substrate of the "miracle mud." Oh, sigh...I can't even go into it all. Don't have it in me to go though all the decpetion perpetrated by those with no clue.

Anyway, the N limitation and unusual ratio is interesting, and shows adaptation to certain environs in the wild...Kaneohe Bay is a long term experiment in nutrient enrichment and all sorts ofinformation has come from there. Caulerpa in tanks, its possible that it could shift dominance to other species and in general agree with parts of most of the posts here from Graham and Howard - with real happenings in tanks speculative, though. The reasons to not use Caulerpa are many and this could potetially be one.

[Rick Davis]

FWIW, I kept an Ecosystem in my 60 gallon tank for almost a year and about 3 months ago the caulerpa growth really slowed down while the turf algae in the main tank increased (no tangs). Now there caulerpa is kaput and I will not be using Ecosystem on my new 180. I have a healthy growth of several turf algaes in the main tank that I siphon harvest from time to time.

My experience matches what Eric has been saying in his Mything the point articles.

1. Caulerpa is an uncommon algae on the reef. I lived in Hawaii for 10 years and rarely saw any caulerpa patches and the ones I did see were in shallow tidepools.

2. Turf algaes in the main tank under metal halides will definitely outcompete caulerpa in a fuge for nitrates and phosphates.

3. Turf algaes (in general) have more P in the N:P ratio so they are removing more P than caulerpa.

So my next tank will have a small turf algae section in the fuge just for a little reverse photo period impact and I plan on continuing to harvest turf algae out of the main tank as the primary algae export technique.

[reefhorse]

Very interesting discussion. I have 4 systems running for over a year - some with fuges , some with skimmers. Initially all were producing lots of caulerpa and chaetmorpha. One tank was designed to be a macro algae tank. Got to where it was quite nice with lots of different caulerpa - but had 2 crashes and have discontinued the experiment. Now all my fuges have very little caulerpa or chaetomorpha (1/5 of previous levels). I attributed this to my marine experence and ability to control nutrients. The above discussion is teaching me some humility.

Am very interested in learning more about turf algae (Googled turf algae but did not get good references). And to see if anyone has set up turf algae fuges.

Sincerely,
John Ason

[G-money]

Check the forums for "algal turf scrubber" or just "turf scrubber"..
This is currently the most effective way to utilize turf algae for nutrient removal.

It's fairly labor intensive in that the screen the algae grows on must be harvested pretty often and you need to make sure the turf stays contained in the scrubber. You also need to make sure flow to the scrubber is maintained. The units are kind of expensive as well, if I remember correctly. I haven't looked into them in a couple years, but I have seen a couple in operation and the users have been pretty happy with them.

Eric has a fair bit of experience with these I believe ...

[Dag]

So what is turf algae ...?

[G-money]

Turf is a general name for a plethora of low-growing filamentous (micro)algae species. They rarely grow much more than 1cm in height and are heavily grazed on the reef. Many damselfish sp. guard patches as territory. I did a paper on this a few years ago that (for one) explored the effects of removing local damselfish from their turf patches. The patches were soon consumed (within minutes in some cases) to stubble by various herbivores (mostly surgeonfish).

Turf sp. are very efficient at trapping sediment, so I think that may be a big reason why they are able to outcompete macros - not to mention they have more surface area (per mass) than macros. I'm not too familiar with their physiology, so I won't go there - maybe Eric can help you with that. They are considered a threat to corals if they are allowed to grow unchecked...they are very likely growing in areas of most systems with reduced or largely absent herbivory. I have some in my overflow...

[piercho]

Am very interested in learning more about turf algae

Walter Adey describes a method to maintain aquatic ecosystems using harvest of turf algaes in the book Dyanamic Aquaria. It's a good book if your interested in learning about this hobby from the viewpoint of building a viable model of a natural ecosystem. A bit academic for some people.

[Thaxx]

Originally posted by Graham
Check the forums for "algal turf scrubber" or just "turf scrubber"..
This is currently the most effective way to utilize turf algae for nutrient removal.

It's fairly labor intensive in that the screen the algae grows on must be harvested pretty often and you need to make sure the turf stays contained in the scrubber. You also need to make sure flow to the scrubber is maintained. The units are kind of expensive as well, if I remember correctly. I haven't looked into them in a couple years, but I have seen a couple in operation and the users have been pretty happy with them.

Eric has a fair bit of experience with these I believe ...

If these are that expensive, and labor intense, wouldn't water changes be just as good?

[EricHugo]

>>If these are that expensive, and labor intense, wouldn't water changes be just as good?<<

Well, of course! It always comes down to that. The limitations of closed systems become non-existent if water chnages become frequent enough that they are effectively open systems (of course, salt mixes aside)...But, it seems that all manner of effort and expense are part and parcel of the reef hobby in some sublime effort to avoid doing the simplest, cheapest and most effective water purification possible...the water change.



>>Walter Adey describes a method to maintain aquatic ecosystems using harvest of turf algaes in the book Dyanamic Aquaria. It's a good book if your interested in learning about this hobby from the viewpoint of building a viable model of a natural ecosystem. A bit academic for some people.<<

Great book, and that together with the papers that stemmed from the turf scrubber are the reference sources for this infomation.

>>Turf is a general name for a plethora of low-growing filamentous (micro)algae species. They rarely grow much more than 1cm in height and are heavily grazed on the reef. Many damselfish sp. guard patches as territory. I did a paper on this a few years ago that (for one) explored the effects of removing local damselfish from their turf patches. The patches were soon consumed (within minutes in some cases) to stubble by various herbivores (mostly surgeonfish).

Turf sp. are very efficient at trapping sediment, so I think that may be a big reason why they are able to outcompete macros - not to mention they have more surface area (per mass) than macros. I'm not too familiar with their physiology, so I won't go there - maybe Eric can help you with that<<

You are doing great all by yourself. They are extremely, though variably productive, highly grazed, and generally not well chemically defeended, their life history trait being fast growth as a mode of dominance and spread rather than chemical or physical defenses

>>
This is currently the most effective way to utilize turf algae for nutrient removal.<<

agreed

>>It's fairly labor intensive in that the screen the algae grows on must be harvested pretty often and you need to make sure the turf stays contained in the scrubber. You also need to make sure flow to the scrubber is maintained. The units are kind of expensive as well, if I remember correctly. I haven't looked into them in a couple years, but I have seen a couple in operation and the users have been pretty happy with them.

Eric has a fair bit of experience with these I believe ...<<

Yeah, I have one in the attic I need to sell on eBay. I wouldn;t say the labor is any greater than regular dimantling and cleaning of skimmer and pump, and the labor goes down the longer and more mature is the turf screen as it is successional. the long filamentous hair algae prone to amphipod infestation and frequent scraping eventually gives way to short tufty stiff species that rarely require scraping and are much more resitant to amphipod damage. Furthermore, the nutrients eventually become so low that the turfs are even N limited. the turfs don;t spread to the tank because they are eaten unless there is a total lack of herbviory and no amphipods in the tank at all....unlikely.

My biggest complaint was the water flow issue. the dump tray didn't provide enough. You could just add powerheads, of course, which I did...but initially while working with it I wanted to stick strictly to the ATS paradigm.

I don't use it anymore because it was designed for a tank size of whcih I no longer have - 30-55 gallons.

>> And to see if anyone has set up turf algae fuge<<

You really can't - the bugs eat them. Yu would have to make a bug proof refuge and then maybe it would happen. For example, when I take a tank and set it up with sand and tank water and hit it with light with no grazers, I get tons and tons of turf algae...basically pure primary production. So, you'd have to screen it from pods, snails, and obviously no urchins or surgeonfish, etc.

[ayrton]

Skim your tank heavily and wet and you will likely vastly outperform any and all methods of export aside from very large water changes and major biomass removal on several levels.

Hi Graham
what do you mean with "skim haevily and wet "

Thanks

Lorenzo