Debating the pros and cons of turf algea scrubbers

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pat8you

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So before i start i would like to say that i am making no judgements for or agenst turf scrubbers at this point. I read over your thread at RC and agree that some of the users there, while offering some valid critisims, were very harsh and things did seem to get out of hand quickly which took away from the more educational debate on the benifits and drawbacks of this system.

I also watched the video that they linked you to about the causes of the death of corals. While i will admit that is was quite technical and some of it was a bit out of my reach i will say that it did bring up some concerncs about this system. It did mention that turf algea in close proximty to corals (i assume they were talking about SPS) did cause an increase in pathogins and led to the death of the corals in about 24 hours. I was unsure what exactly they meant by "close proximity". They were discussing this in the natural enviroment of the coral and in lab experiments. So in the ocean close proximity could be with in a few hundred feet and in lab experiments this could be 2 inches. I was wondering if anyone could clarify how close the algea has to be in order to kill the corals. Since our aquariums are closed systems i wonder if this would even matter if they are close or not becuase aside from water changes anything that the algea leeched into the system that would kill corals would eventually build up in the water. Later in the video they discussed how a high concentration of DOC matter seemed to directly relate to the health of an overall reef. This seems to favor a system like algea scrubbers as opposed to skimmers which would take out much of the DOC's.

It would be helpful if some of the more educated people on this topic could link a few articles that are scientific and factual in nature as opposed to opinions or semi-experimental home trials. I would do an internet search my self but i fear that i don't know quite enough to sort out which articles are writen by credible sources and which articles are bias views that may not be entirely true. I'm looking for articles both for and against the system so i can make an educated decision if this system would be a good choice for the type of reef system i am looking to set up.
 
It did mention that turf algea in close proximty to corals (i assume they were talking about SPS) did cause an increase in pathogins and led to the death of the corals in about 24 hours.
That was the controlled test they did to set up the reasearch, assuming that higher DOC would mean weaker or no hard corals. Remember, he says that it's "something else" that's killing the corals, and that the algae may just be filling in as a result. That point in the video was also where the other folks stopped watching, assuming that was all they needed to see. The other folks' main point all along was: Using algae instead of skimmers will increase DOC, and microbes, and will kill hard corals. What the video research actually found in the ocean (and I quoted in text) was: The increase in DOC actually led to a decrease in microbes, and healthier hard corals. "Close proximity" I believe, was when they were testing in-tank, and they were almost touching, with a sub-micron mesh between them. Not real life.

I was wondering if anyone could clarify how close the algea has to be in order to kill the corals
You are thinking that the controlled test is really actual conditions. The controlled test used a sub-micron mesh between the two, which stopped the full flow of whatever normally flows between the two. This would not be present in real waters. Remember, all tanks have algae, any many tanks have turf algae, and they all grow hard corals including SPS. I'm compiling a list of those folks now by the way. The public aquariums of the past who had trouble with SPS all had two things in common: They did not clean the screens once a week, and when they did clean/scrape them, they did it in-system (because they were too big to remove). Either of these circumstances would cause a turf screen to fail it's mission if you tried it at home.

Now, if you had a large collection of SPS that had been growing for years, I would not tell you to dump everything for a scrubber. I'd say add a scrubber first and go from there. But for folks starting out, they aren't going to have an SPS collection that had been growing for years, and probably shouldn't have any SPS at all. So the whole video research thing is kind of moot as far as the purpose of this thread. Those other folks introduced it as evidence for them (without even watching it), and when I showed them that it actually dis-proved them, they never said another word about it. I wonder how many free skimmers they get from manufacturers.

Later in the video they discussed how a high concentration of DOC matter seemed to directly relate to the health of an overall reef. This seems to favor a system like algea scrubbers as opposed to skimmers which would take out much of the DOC's.
Correct. That's what the other folks never even bothered to watch. And it was their own evidence that they found and gave to me. That's when I stopped trying to prove anything to them; if they won't watch their own evidence, they sure aren't going to look at mine.

It would be helpful if some of the more educated people on this topic could link a few articles that are scientific and factual in nature as opposed to opinions or semi-experimental home trials.
Do start a new thread about that. And let's keep this thread about building screens and removing N and P from systems, which it is proven to do. After beginners have removed the nuisance algae from their tanks, then they can start further research on your new thread to see if they want to pursue SPS tanks with turf-only filtration. :)
 
Well i went back and watched parts of that video again to make sure i understood the conditions of their test. You are correct and they had the algae right next to the coral with a very fine screen that would only allow dissolved material to pass through it. The purpose of this test was not focused on DOC's however. The conclusion of the test was that the algae was producing "something" that encouraged the growth of microbials that stressed and ultimately killed the coral. Here is the quote from the movie that confirms this at around 15:19

"this suggests that there is something dissolving out of the algae talking to the coral and killing it, but there is a microbial intermediate."

Now i understand that this is far from the real situation in the wild where there would be a much larger separation between algae and coral and a much larger volume of water to help disperse what ever is being put out by the algae. The leads me to believe that there is some other mechanism that controls the population down to a tolerable level to the corals in their natural environment and prevents them from building up in the water column. The reason this concerns me is that we are dealing with closed systems (our aquariums) where these things could easily build up. I'm hoping someone else can step in an possible tell us how this can be prevented. Water changes being the obvious solution here but is there any other natural methed of controling these microbials? Could it be that they can be removed by a skimmer or possibly by a deep sand bed?

Another concern i have with the ATS system is that while like santamonica mentioned that all systems have algae and some even have turf that has grown on overflow boxes or sump walls. It is in relatively small amounts compared to what we are talking about growing intentionally on the screen. In the movie they seems to think that turf algae was far worse then any other kind of algae they tested. 16:20

"here we used a whole bunch of differnt algaes and what i can tell you is that turf algae was way the most disterous ... you put a turf algae next to a coral and the coral would be dead in a couple hours really"

While you have said that there are many succesful SPS systems that run ATS filtration i assume that they are also running other methods that would help prevent what ever the turf algae releases that kills corals from building up to a toxic or stress inducing level. My point here is that i'm not willing to risk running an ATS set up with out knowing what exactly i need to do in order to prevent these kinds of problems and establish something that mimics the natural health enviroment.

These things lead me to believe that for any system that includes SPS corals ATS filtration cannot be the sole method of filtration. Also i don't think that ATS or any filtration system should claim that it can eliminate the need for water changes for the simple fact that we still do not fully understand everything involved in a reef ecosystem and we don't know what could be building up in the water of our closed systems.

In any case i'm not taking into consideration the lack of success that a few of the larger institutions had with ATS and SPS corals for the simple fact that it could be any number of reasons that these corals died which may not be related to the ATS filtration at all. Simply to many unknowns in that equation. Simiarly i will not accept the fact that there are some people running ATS filtration and have thriving SPS systems as proof that ATS does not have the possiblity to cause serious problems with these corals. Again there are to many other possible explanations for the success including that we don't know the time frame that these corals have been kept alive or what losses have occurded but been looked over as unavoidable deaths that are just part of the hobby.

After doing some reading my last concern with the ATS system is the rumor that it will tint your water possibly yellow. I've heard claims ranging from it will turn the water pee yellow (for lack of a better discription) or as minor as a slight tint that is harly noticable.

This question was posed on an article writen by Morgan Lidster who represents Inland Aquatics who is a strong advocate for ATS. The link will be posted at the end.

There have been several people who have supposedly visited IA who have stated the
systems looked very dirty and the water was green. Is there validity to this?
Who? I've never had anyone report that to me....? I've had some
pretty big skeptics here and have yet to know of anyone who did not have a positive
response. .... Our water is not as clear as many Berliners, but we do not strive for
it to be... We are working toward the goal of effective model microcosms and commercial
mariculture. I suspect someone expected to see all living room type set-ups when they
visited

Now Morgan him self admits that he is bias towards this system. While i find it hard to believe that their systems actually look bad i do get a hint from this responce that there is a noticable difference in water clarity that he writes off to modeling the natural enviroment. I would be interested to know or see for my self the actual difference from someone who is not bias.


In any case i'm wondering if anyone can enlighten me as to what causes this discoloration of the water. I understand that there is a higher consentration of organic material in the water but i wouldn't think this would color the water green or yellow and the natural enviroment while having a high concentration of organic material doesn't have any sort of color to it. I've heard rumors that the turf and other algae can put a lot of algae spores into the water. Could this be a possible explanation for the color?


Please keep in mind that i am not trying to make any sort of a personal attack to any statements made by santamonica but simply seeking an objective evaluation of this system. Because santamonica is an advocate i am forced to play the other side of the coin. At this point i have not passed any judgement on wether the system is good or bad. Here are a few of the links i've been reading over thanks to Melose and Innovator


Reefs.org: Where Reefkeeping Begins on the Internet - View Document
Refugium article
The Natural Reef Aquarium
:: The Algal Turf Scrubber ::


There are more but i'm running out of time here.
 
I would like other more knowledgeable folks to deal with this, but I'll get it started...

The leads me to believe that there is some other mechanism that controls the [microbial] population down to a tolerable level to the corals in their natural environment and prevents them from building up in the water column.

Yes and I think that the mesh they added prevented this X factor from happening. Of course in our tanks you still have the X factor.

The reason this concerns me is that we are dealing with closed systems (our aquariums) where these things could easily build up

But you have the X factor building up to. It has to, there are too many tank with algae-only filtration and hard corals that have been developing for years. Something is causing them to thrive.

is there any other natural methed of controling these microbials

Remember in the video, they said that (surprisingly!) higher DOC corresponds to LESS microbes. So to answer your question, apparently removing the skimmer will raise DOC and give us less microbes.

In the movie they seems to think that turf algae was far worse then any other kind of algae they tested.

That's why turf (real red/brown stiff carpet-like stuff) is the most powerful; when provided with enough light and flow and turbulence, it processes the most N and P per unit size. What they are saying is that this higher processing has more X factor too. Also rembember the part where they talk about the possibility of corals dying from something else, and algae then filling in the dead spots.

"you put a turf algae next to a coral and the coral would be dead in a couple hours really"

Yes in the controlled test that's what you want; it helps you identify the X factor. Eliminate different things so that the corals die the fastest, then try to determine what you eliminated. Then that would be your X factor. In the video, they now know that the X factor was physically too large to get through the sub-micron mesh. So that tells them something about it.

While you have said that there are many succesful SPS systems that run ATS filtration i assume that they are also running other methods that would help prevent what ever the turf algae releases that kills corals from building up to a toxic or stress inducing level.

No not at all. And that's my point about the X factor. Many tanks have nothing else but algae, and grow great SPS long term. So the X factor keeps the microbes down, even though DOC is high. Who knows, maybe it's part of the DOC.

My point here is that i'm not willing to risk running an ATS set up with out knowing what exactly i need to do in order to prevent these kinds of problems and establish something that mimics the natural health enviroment.

Of course. In your situation, I'd say consider adding one to your existing filtration and watch things for six months.

Also i don't think that ATS or any filtration system should claim that it can eliminate the need for water changes for the simple fact that we still do not fully understand everything involved in a reef ecosystem and we don't know what could be building up in the water of our closed systems.

Well keep in mind my original thread said the WC can be eliminated if the purpose of the WC was to reduce N and P. So this remains true. It does not apply to other reasons for WC's. However, if not doing WC allowed (positively absolutely) bad things to build up that would kill corals, then you would not have long-term healthy tanks with no WC. But you do. So another X factor at work there. Nevertheless, most people who do WC's are doing to to reduce N and P.

In any case i'm not taking into consideration the lack of success that a few of the larger institutions had with ATS and SPS corals

Me either. Just the fact that they scraped in-system, and also that they sometimes let their screen go uncleaned forever, is enough for me to see why they failed.

Simiarly i will not accept the fact that there are some people running ATS filtration and have thriving SPS systems as proof that ATS does not have the possiblity to cause serious problems with these corals.

Correct, it does not prove that. What is does prove is that whatever is killing the SPS (in some algae-only filtration tanks) is not the algae itself; it's something else. If it were the algae itself, then every SPS tank would die. And keep in the mind the number of non-algae SPS tanks that die. Thousands. So it might not be related to algae at all, but some other husbandry issue.

After doing some reading my last concern with the ATS system is the rumor that it will tint your water possibly yellow. I've heard claims ranging from it will turn the water pee yellow (for lack of a better discription) or as minor as a slight tint that is harly noticable.

Ahh this is a simple one. Turns out that when you scrape in-system (like all public aquariums did, and like home user did until about 4 years ago), the broken algae strands release their contents into the water. Boom... instant chlorophyll-laden water. The small screens that we are working with now are self-correcting in that respect, since you have to take them to the sink for cleaning/scraping. I know my water is crystal clear with regards to color; I even posted pics on RC comparing the color of my water looking through my tank at a window, to looking at the window through the air; no difference.

Now Morgan him self admits...

Same thing here... their huge scrubber screens are not removed and cleaned in sinks; instead everything stays in the water. But like he says, they don't care... they're just growing corals. By the way, I've not read of one report of users in the last couple years that had yellow water, and certainly nobody that's built a screen from my thread has had any. All due, of course, to taking the screen to the sink to clean.

Here are a few of the links

Good info. Already read three out of four :)
 
The reason this concerns me is that we are dealing with closed systems (our aquariums) where these things could easily build up

But you have the X factor building up to. It has to, there are too many tank with algae-only filtration and hard corals that have been developing for years. Something is causing them to thrive.

What ever it is that reduces the microbial population does not necessarily HAVE TO build up as well. Your using successful SPS systems as proof which as i said before i will not accept. There are also other SPS systems that reported miserable failure using ATS. At inland aquatics he mentioned that they use only ATS on their tanks but he also mentions using very deep sand beds in almost all thier systems as well. DSBs are another very effective method of filtration as well as live rock so it technicly isn't their sole method of filtration. It could be bacteria in the DSBs that reduces the microbial population. We just don't know what exactly it is that does this which is why i am saying that using it as the "sole" filtration seems to be hit or miss. Some thrive others fail.

is there any other natural methed of controling these microbials

Remember in the video, they said that (surprisingly!) higher DOC corresponds to LESS microbes. So to answer your question, apparently removing the skimmer will raise DOC and give us less microbes.

They said that in the natural environment their was a consistent trend that areas of high DOC concentration there was lower microbials but they did not say that the higher DOC concentration was the cause of this. So i think its a bit of a leap to say that removing the skimmer and having higher DOC will automaticly give you less microbials.

Simiarly i will not accept the fact that there are some people running ATS filtration and have thriving SPS systems as proof that ATS does not have the possiblity to cause serious problems with these corals.

Correct, it does not prove that. What is does prove is that whatever is killing the SPS (in some algae-only filtration tanks) is not the algae itself; it's something else. If it were the algae itself, then every SPS tank would die. And keep in the mind the number of non-algae SPS tanks that die. Thousands. So it might not be related to algae at all, but some other husbandry issue.

I understand that its not the algae directly killing the corals but the test they did does prove that the algae indirectly causes thier death through some chain of events. Until we know what intermediate process prevents this in the natural enviroment and can ensure the ability to mimic this intermediate process in our systems i feel that the ATS system will still pose a possible threat to SPS systems.

Ahh this is a simple one. Turns out that when you scrape in-system (like all public aquariums did, and like home user did until about 4 years ago), the broken algae strands release their contents into the water. Boom... instant chlorophyll-laden water. The small screens that we are working with now are self-correcting in that respect, since you have to take them to the sink for cleaning/scraping. I know my water is crystal clear with regards to color; I even posted pics on RC comparing the color of my water looking through my tank at a window, to looking at the window through the air; no difference.

Ok i'm sure that if you scraped all the algae back into the water it would turn things a funny color which may be where some of the more extreem reports of yellow or green water came from. On the other hand i highly doubt that educated professionals working at public aquariums or the people at Inland Aquatics would be silly enough to scrap that stuff back into thier systems. That would be completly defeating the purpose of the ATS system as this would release all the stored garbage in the algae right back into the water. There has to be another explanation for the tint in the water. Is it possible that a small amount of the turf breaks free from the screen and gets back to the water?
 
by the way. come on people someone else jump in on this. the more people that take a few minutes to look into this the more information we will be able to find.
 
Oh hum, I don't feel like arguing. I will say that I agree with the public aquarium and commercial institution comment by pat and that many turf scrubbers are/were designed on a rack/drawer system for easy removal and cleaning outside of the main system. This would make absolutely no sense otherwise and not only waste their precious time, but their money. As to your question, more than likely when the algae is forming across the mesh they are also reproducing, sexually and asexually, releasing spores and tinting the water. When the screen is cleaned it levels the competition by allowing more algae to reproduce and grow upon that fresh screen. This in turn could have negative effects as well, by causing more nutrient uptake competition while interfering with photosynthesis with corals and depleting the availability of organics for corals to utilize. Depending on dynamics of a system, the DO (Dissolved Oxygen) could come into play as a direct relation of availability for coral respiration. This can be seen in the natural state where reefs, being abundant in nutrient compositions, quickly utilize food sources and herbivores maintain efficiency vs. DOM concentrated estuaries and coastlines (going with eccentrics here). Saltwater blackwater? There is a balance in both views whether it is what you expect from your system or not.
 
he also mentions using very deep sand beds in almost all thier systems as well. DSBs are another very effective method of filtration as well as live rock so it technicly isn't their sole method of filtration

Correct. But I don't think reefkeepers think of rock as an optional filter; you pretty much have to have it to have a reef. And I'd say almost the same for sand, except that I got rid of my DSB. So for "filters", I mean any kind of add-on that you buy or build.

They said [in the video] that in the natural environment their was a consistent trend that areas of high DOC concentration there was lower microbials but they did not say that the higher DOC concentration was the cause of this

Correct. The only reason I brought it us was because the main argument made by the folks that offered up the video was that "high DOC kills corals, and without a skimmer you get hight DOC". So yes, without a skimmer you get hight DOC, but the surprise is (from their own video) that you get lower microbes. Fortunately my line of work does not require me to do follow up reasoning for this; I'll leave that for the researchers, then I'll read it.

Until we know what intermediate process prevents this in the natural enviroment and can ensure the ability to mimic this intermediate process in our systems i feel that the ATS system will still pose a possible threat to SPS systems.

Well then what you need is a controlled test of X number of identical SPS tanks run with a skimmer, and the same number run without. And see if there is a change in the number that die. Certainly some of both groups will. Could be an easy test, maybe a 10g on a small skimmer in the first group, and a 10g on a small scrubber in the second group.

Ok i'm sure that if you scraped all the algae back into the water it would turn things a funny color which may be where some of the more extreem reports of yellow or green water came from. On the other hand i highly doubt that educated professionals working at public aquariums or the people at Inland Aquatics would be silly enough to scrap that stuff back into thier systems.

No no, you are not dumping the scrapings back in; it's the residual liquid contents of the broken algae strands that drain back in.

many turf scrubbers are/were designed on a rack/drawer system for easy removal and cleaning outside of the main system.

I have not uncovered one occurance (and certainly not of the huge public aquarium ones) that had its screen removed before cleaning, before just a few years ago.
 
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