Algae issues? Why dont more people use algae scrubbers?

[Garf]

I'll give a little more detail on these points because I think they're good!

These are all good effects and my model wraps them all into this "intrinsic growth rate per unit volume"


We can solve for the relations between the variables and model what the curves look like under different conditions (a type of simulation). That's what the curves demonstrate below the model!



As mentioned in the first reply, this is already included with df/dt and is assumed to be a constant rate of nutrient influx.



This is certainly an effect but my model assumes that the tank is rapidly mixed. I think it's a reasonable approximation since the flow inside/through tanks, temperature/diffusion times would mix the nutrients faster than they will be depleted.



And thanks again for reading this and giving feedback!!

ok, the rapid circulation part would also be complicated ratio between flow, surface boundary layer and Overall algal surface area. How the hell you’d get your head around that is beyond me, lol.

 

[BeanAnimal]

He patented “bubbles” as a method of circulation in regard to growing algae on a screen, as far as I remember.

I stopped paying serious attention shortly after it became obvious that his "contributions" to one of the original ATS threads were aimed at building a business and writing his own "science", relating things to "cubes per day", etc. I (honestly) have no problem with SM or his business and think that it is great that he has been rewarded with a patent, success, etc. I just don't do well with the made up nonsense that fills the gaps.

 

[BeanAnimal]

ok, the rapid circulation part would also be complicated ratio between flow, surface boundary layer and Overall algal surface area. How the hell you’d get your head around that is beyond me, lol.

I don't think you can easily get the math around it, even if you can get your head around it. I suppose with some experimentation you can create a few black box constants, but even then...

 

[Thales]

Get ready for excitement! I'll demonstrate the power of a good model!

To alleviate confusion around this, I decided to model the effect of a refugium/ATS and prove that growing algae in one location will have an effect on the amount of algae grown at a different location (and even has the ability to make it go to 0).

Consider the following setup of a display tank and a refugium/ATS with volumes of V0 and V1, respectively.

The Nutrients (N) in the tank are considered "well mixed", which means that the concentration is instantaneously equilibrated, and local effects are not considered, i.e. algae in the display has access to the identical nutrients in the refugium/ATS and vice versa. p0 and p1 are intrinsic rates of nutrient intake per unit volume for the display tank algae and fuge/ATS algae, respectively (these values are different because of lighting power/spectrum differences, etc. but could also be more general to measure of other factors too).

With this setup, we can model a set of differential equations that describes the change in nutrients in the water column, as well as nutrients that accumulate in algae from the display tank or fuge/ATS.

Here, N(t) is the amount of nutrients in the water column, A0 is the amount of algae in the display, and A1 is the amount of algae in the refugium (both A0 and A1 are in units of nutrients). We can also model a constant influx of nutrients to the tank (i.e. through feeding). In this model, I assume no outflow of nutrients, so the sum of N, A0, and A1 is always increasing by c*t.

Solving these differential equations for N, A0, and A1 yields the following:

Now the neat thing about this is that the growth of algae in the display is proportional to the ratio of intrinsic growth of the display and its volume by the total algal growth (p0V0 / (p0V0 + p1V1)). If we take this to the limits and have a significantly larger Fuge/ATS than the display tank, we can see the algae growth in the display tank goes to zero!

This is a proof that your model is wrong! Algae grown in one side of the tank *DOES* influence algae grown at another, and a sufficiently large fuge/ATS *CAN* completely outcompete algae in the display.

So, finishing our discussion: if a fuge/ATS doesn't work, it's NOT because algae grown at one location can't compete with another location.

Backing up though, how many of us have a fuge/ATS that's larger than our tank?? I doubt many! So what might these curves look like in practice? Well, I computed the nutrient/algae growth as a function of time from the above derivations and there's some informative data!

First, imagine we have a fuge the same size at the display, with identical lighting power/spectrum. Both A0 and A1 curves are the same (green and red respectively, though green is completely overlapped by red in this plot; free nutrients as black curve) and the ratio of algae in the display and in the fuge is 1 (seems reasonable!). BTW, code is in python and available on request!

Next, convincing ourselves that it's possible for a mega sized fuge (100x the display with a comparative advantage of 10x!) to completely out compete the display tank. A0/A1 ratio is 0.001(this value actually just ends up being the ratio of (P0V0)/(P1V1) so I'm dropping it from subsequent plots.

Okay, I know you're saying this isn't realistic! So what about a fuge that's half the size of the display (still a big fuge) with lights that give a 10x advantage (this is a guess but we can throw this parameter around). Doesn't look too bad! definitely helps, but this model predicts significant algae still growing in the display (green curve).

What about a significantly smaller ATS (5% of tank volume) with bigger advantages (50x comparative advantage to display)? Similar split.

What if we have an underpowered fuge/ATS? lets say same size as above but only a 10x advantage to the display?

Now the algae in the display starts to win! Though its important to notice that the display algae is still much lower than it would be without the fuge/ATS.

Now, I wouldn't read into exact values (a little arbitrary), but this shows how we can tune the knobs of our system and how it will influence the tank!

Summarizing the whole discussion, this model is actually *consistent* with a lot of what you say and actually serves to validate your experience. It's clear that in some circumstances, an ATS and fuge is not "all you need" (though to be fair I'm not sure anyone has actually ever said that in this thread lol).

It is consistent that even with an ATS, you and others can still see algae in your display tanks. However, it is clear that an ATS can work, but might need to be supplemented with some other practices that add to the comparative advantage, like... herbivores!

The big difference, and the reason I've been persistent is that your explanation of "why" just didn't hold water (pun intended lol).

I hope you have a great Tuesday!

Sweet. You are catching up by working it out yourself. In addition to what garf said above, almost all of us agree that a big enough algae farm will help manage nutrients (IIRC we calculated that for the 200,000 gallon reef tank at Steinhart, we would need an algae farm bigger than the area of the buildings roof) - leaving aside the discussion of how much or if those nutrients really need to be managed or is allopathic compounds from the algae are problematic.
Next step is to see if the models hold up in practice, which is where the discussion has stalled for 10 years or so. Then you can start to decide if the juice of an ats is worth the squeeze - if you are going to need to add herbivores anyway, and herbivores can manage algae even at high nutrient levels without ats, why add the extra work and cost and system complexity?

You do keep saying that my model Is wrong, then you talk about things I don't actually think. Did you look up any of the articles or talks I mentioned earlier? Or read any of the Addy stuff?

My second post in this thread (the first was asking questions) FWIW -
"I could never get an ATS to make much of an impact on my system. I have tried several.

I don't see much compelling evidence to support the idea of growing algae in one place resulting in algae not growing in another - without other actions implemented at the same time."

Thanks!

 

[MarineandReef Jaron]

Well, I am a bit late to the party but I thought I would chime in.

I do not think ATSs are a miracle product but that doesn't mean they aren't good. I have been reefing long enough to know that there are many ways to keep a reef tank. One key part of keeping a reef tank is nutrient control. I have never had a reef tank that has not needed some strategy for Nitrate and Phosphate control. I see some people say that I just don't have enough corals, but really I think it is that I have a lot of fish. I may be one of those weirdos who gets more excited about fish than corals but I just can't resist adding more fish to my tanks. They are great. Even tanks with large colonies will still need nitrate and phosphate control if you have a lot of fish.

There are 3 general paths I have found for controlling Nitrate and Phosphate. All work and have their place.

1. Do a lot of water changes
2. Algae filtration
3. Bacterial filtration

Firstly doing a lot of water changes works really well. Some of the best tanks I have kept were nano tanks with nothing but a hang-on filter and weekly 50-70% water changes. This still may be one of the most simple ways to achieve reefing success. The problem is if you have a large tank the amount of work and money involved in doing this many water changes just makes it unreasonable. For my 12-gallon desk tank I can spend less than an hour a week cleaning it and have a beautiful tank on my desk without needing to mess with any complicated equipment, for my 200-gallon home tank doing weekly 50% water changes would just be impractical.

Algae filtration does work whether it be an algae refugium or turf scrubber. Where the ATS really shines is that it is a lot more idiot-proof than a fuge. With a fuge, you need to decide on the refugium area, the flow rate, the lighting, and a source of healthy pest-free algae. With an ATS you simply buy a premanufactured unit and plug it in. I also find that the turf algae is hardier. I have had chaeto crash likely from micronutrient limitation. The turf algae can live through almost anything and even if it dies you do not need to go buy some more algae you simply wait and the algae will recolonize on its own.

Bacterial filtration through anaerobic filters and carbon dosing is very very effective. As a general principle of ecology the simpler the organism the more effective it is at capturing all available nutrients from a given source. For example, your fish capture nutrients from the food you feed but the clean-up crew can capture more nutrients from the feces of the fish, and then algae and bacteria can capture even more nutrients from the remains of the clean-up crew. Because bacteria are about as simple an organism as is possible bacterial filtration is extremely effective. This is why most ULN systems use bacterial filtration. The biggest advantage of bacterial filtration IMO is that it is much easier to control and does not require large equipment. You can simply add a liquid carbon source and watch nutrients go down. If they drop too much you dose less, if they are not dropping enough you add more.

So why not use a turf scrubber?
Do I really want to install a turf scrubber on my nano tank when I can control nutrients with regular water changes? Can I fit an algae turf scrubber into my AIO? Would I rather have the ability to easily dial the nutrient removal up and down with my dosing pump app? Do I want to spend several hundred dollars upfront when I can just add some vodka in every day?

There are plenty of reasons to use another method, but that doesn't mean turf scrubbers aren't useful tools.

 

[VintageReefer]

Can I fit an algae turf scrubber into my AIO?

You can with the slip .7 model which slides in the back of a aio chamber - it can also be configured to be a cheato reactor if that floats your boat instead

And to summarize this thread, yes they are a useful tool, yes they absolutely can and do work to control display algae. But that doesn’t mean it will prevent or fix every situation out there! And it doesn’t mean it’s the be all end all best solution out there! There are many methods to reduce and eliminate algae, and an ATS is one of them

 

[MarineandReef Jaron]

You can with the slip .7 model which slides in the back of a aio chamber - it can also be configured to be a cheato reactor if that floats your boat instead

I like these but what I think is stopping them from catching on is the $200 price tag. I find it hard to sell nano skimmers over $150 and the $99 nano skimmers sell very well. The slip .7 would be a great product if it was $99.

This would require moving production to mass manufacturing overseas which Santa Monica has not been wanting to do. I hope we will see some more affordable nano scrubbers in the future.

 

[flashsmith]

I've never had an algae issue over many different systems. I guess stocking things that that eat it and carbon dosing work. Oh and just cleaning things does wonders too. Check the simple things first.

 

[VintageReefer]

I like these but what I think is stopping them from catching on is the $200 price tag. I find it hard to sell nano skimmers over $150 and the $99 nano skimmers sell very well. The slip .7 would be a great product if it was $99.

This would require moving production to mass manufacturing overseas which Santa Monica has not been wanting to do. I hope we will see some more affordable nano scrubbers in the future.

I hear ya on the price point. I’ve waffled on buying one at this price. For 99$. Yea it’d be in my tank by now

 

[VintageReefer]

I've never had an algae issue over many different systems. I guess stocking things that that eat it and carbon dosing work. Oh and just cleaning things does wonders too. Check the simple things first.

I’ve never had algae issues <Admits to using carbon dosing + relying on critters to eat it + cleaning it manually>

Clean things? Check the simple things? Thanks for the tips and for adding value to the thread.

We all would have algae issues if we didn’t rely on means to control it. Just because someone found a way to control it doesn’t mean they still don’t have the issue. it’s nature. Algae grows unless you actively combat it in some way

 

[GARRIGA]

Patents or not, I don't remember it being that cut and dry or glossy and while SM may have worked very hard to build a patentable product, he didn't invent turf scrubbing and in fact there were plenty of us prior to 2012 using ATS in various forms.

Prior to buckets and clip on shop lights, many of ran dump boxes either DIY or commercial units. Dr. Walter Adey coined the term and started working on these and publishing articles about "Algal Turf Scrubbers" in the late 70s and had a patent by 1982.

I had an an Adey ATS sometime in the early 2000's and grew wary of keeping it the dump tray rocking and simply ran it in a fixed position with a better light. Many of us did the same thing. So sure, SM b

Knew of a few LFS staffers who had Rubbermaid containers under their tank with shop lights and Caulerpa before the term Refugium ever happened. Was trying to create that with live rock and sea weed but at the time no access to sea weed. Might now that I do.

Lots from today didn't start today but new to one often think it's new to all. Waiting for UG to get a fancy name and become mainstream again

 

[BeanAnimal]

Knew of a few LFS staffers who had Rubbermaid containers under their tank with shop lights and Caulerpa before the term Refugium ever happened. Was trying to create that with live rock and sea weed but at the time no access to sea weed. Might now that I do.

Lots from today didn't start today but new to one often think it's new to all. Waiting for UG to get a fancy name and become mainstream again

@Paul B still uses a UGF - has for 30+ years
Maybe 40+ years. He's older than me and has better memory, so he can tell you how long.

 

[mizimmer90]

Sweet. You are catching up by working it out yourself. In addition to what garf said above, almost all of us agree that a big enough algae farm will help manage nutrients (IIRC we calculated that for the 200,000 gallon reef tank at Steinhart, we would need an algae farm bigger than the area of the buildings roof) - leaving aside the discussion of how much or if those nutrients really need to be managed or is allopathic compounds from the algae are problematic.
Next step is to see if the models hold up in practice, which is where the discussion has stalled for 10 years or so. Then you can start to decide if the juice of an ats is worth the squeeze - if you are going to need to add herbivores anyway, and herbivores can manage algae even at high nutrient levels without ats, why add the extra work and cost and system complexity?

You do keep saying that my model Is wrong, then you talk about things I don't actually think. Did you look up any of the articles or talks I mentioned earlier? Or read any of the Addy stuff?

My second post in this thread (the first was asking questions) FWIW -
"I could never get an ATS to make much of an impact on my system. I have tried several.

I don't see much compelling evidence to support the idea of growing algae in one place resulting in algae not growing in another - without other actions implemented at the same time."

Thanks!

Questions are great! I also took it that you were asking questions (I even clarified earlier that this is how I viewed the discussion when you thought I was attacking) and have been trying to provide a model for how "algae grown in one place [results] in algae not growing in another" (direct quote above). You have said this multiple times, hence my discussion over the model! See below!

I don't see much compelling evidence to support the idea of growing algae in one place resulting in algae not growing in another - without other actions implemented at the same time.

This is a common way this kind of story goes, which makes it not at all clear that the ATS is responsible for anything you have observed.

This seems like a mind story - I can't think of a compelling reason to believe that algae growin in one place in a system prevents algae from growing somewhere else. We test water, so the 'nutrients' are all over the system.


Starting a weed area in your garden wont stop weeds from growing somewhere else will it?

I don't see how algae in a different part of the system is competing at all with algae in the display - there are more than enough nutrients available all over the system. If the display can grow coral, it can grow algae...

My repeated goal has been to help you understand how algae grown on one part of the tank can influence algae grown at another. The answer is in comparative advantages.

Your model, which is that algae grown at one part of the tank cannot affect algae grown at another, is provably wrong. It doesn't make sense physically.

Again though, I've made careful distinctions that I'm not necessarily arguing in favor of ATSs, refugiums, or making claims as to the size/conditions that will be useful. But your argument that they can't work/haven't worked for others based on your model needs to be thrown out for the sake of science!

Another clarification, I'm trying not to mince my words here and am speaking very bluntly about the models for clarity of the discussion, but I'm not attacking you! I very much enjoy this discussion and think these scientific models can be difficult for people who are unfamiliar to get right away, so clarifications and more discussion is always welcome!

 

[mizimmer90]

I don't think you can easily get the math around it, even if you can get your head around it. I suppose with some experimentation you can create a few black box constants, but even then...

It can be modeled but requires simulations as opposed to derivations as there are no closed form solutions to many body interactions or some of these complex flow equations. I've used chemical engineering softwares to model flows and reaction rates in reactors/various industrial equipment, but I don't have a personal license at this time :/

Edit: I'll point out that these factors can all be implicitly captured in the growth per unit area term in the model. Say the type of flow in one section has a better transport of nutrients at the boundary layer, we can just bump up its intrinsic growth factor term to account for this because it's still just a function of the nutrient concentration.

The values in my model are non physical but the trends will all hold steady

 

[GARRIGA]

@Paul B still uses a UGF - has for 30+ years
Maybe 40+ years. He's older than me and has better memory, so he can tell you how long.

I'm currently running a DIY UG filter. I'm a believer. No convincing needed and yes. I know of Paul. Doesn't treat ich which I'm of the same mindset and have taken the immunity approach with my reptile business since the late 80s. Sediment filtration to maintain vs eradicate what I'm designing next. Not one to just go with new because it's shinny or the latest craze on TikTok

 

[mizimmer90]

Respectfully - while a model and math can "check out" that does not mean that the model is actually realistic or nature will even be close.

For one to "outcompete" the other with a shared homogenous food supply, one would have to be more suitable for consumption. I don't think that is even remotely qualifiable with any reasonable formula for the display or the ATS.

I have played with ATSs for years. Adey dump boxes (very oversized for my tank), buckets and bulbs, waterfall scrubbers and likewise various refugia which are to an extent an analog using the the same nutrients. There are times when one or the other flourish with algea, or both do. There are countless variables. I no longer run an ATS or refugium. I don't see the benefit vs trouble.

I will be the first to quote George box's line that "all models are wrong, some are useful"! I'm a molecular modeler by profession so I am keenly aware of the limitations of models and their applicability to real life data.

In this discussion, I have no skin in the game on the applicability of ATSs and leave that discussion for others with hands on experience to fill in the appropriate values/fudge factors to the models I made.

The original point of this was to disprove the claim that algae grown at one part of a tank cant influence the growth of algae at another!

 

[GARRIGA]

BTW, to put some context to the concept of competition. I performed tests in FW confirming that when organisms overpowered another that the other would be eliminated or minimized. This has been studied I'm sure. This is why I'm of the belief that same organism given a better environment in which to live will out-compete itself in less desirable circumstances. Just so many resources and why one able to consume it faster will survive while the other likely struggles. How all this impacts corals that I don't know yet however they do create their own energy and can be fed directly therefore perhaps the use of an ATS or Fuge to out-compete undesirables in the display could and should work without negatively affecting that we have decided should live for aesthetic reasons. Reefs full of algae that apparently get trimmed by tangs but not all can take that approach. My upcoming 15g cube will have me pursued by the tang police were I so foolish

BRS seems to have proven this with real world examples. I'm surprised the makers of ATS haven't either published their findings or haven't bother to test this theory. Could be I'm completely wrong and their test have conclusively shown the opposite and why not published. Fact is this isn't impossible to validate. Someone with means and space could easily setup additional ATS and keep adding until display solved of that nuisance GHA I'm really really really starting to hate. One manufacturer has apparently validated how many Mysis cubes there's can process daily. How hard can it be to determine what size needed to out-compete everything not hosting a symbiotic entity? Granted all tanks aren't created equal but in a test environment they can.

 

[ScubaSkeets]

At the same time, tons of people swear that they don't work. What is a reefer to do in the absence of data?

I did a Google search on these two terms:
1. Do algae scrubbers work
2. Algae scrubbers "do not" work

After reviewing three pages of results, there were none that said they did not work.

Some said they weren't worth the effort
Some said they worked too good.

Granted, I pretty much just skimmed the results and only opened a handful of links, and perhaps I could have dug deeper,but surely I would have come across one of the "tons of people swear that they don't work"

 

[Thales]

My repeated goal has been to help you understand how algae grown on one part of the tank can influence algae grown at another. The answer is in comparative advantages.

I don't believe I have ever said it couldn't influence, I said it doesn't eliminate or remediate or stop or prevent problem algae in another part of the tank. There is a lot of possible influence possible both ways (there is good evidence that many algea in our systems can be actively chemically detrimental to the corals we keep), and the comparative advantages on their own seem to not be enough in practice in many systems...because algae needs signifigantly less of everyting to grow than that corals most people are keeping. If you go to extremes, sure, but most of the corals we keep in a mixed reef won't be happy, and most of the advantages you can give won't stop algae from growing in the display without additional measures.

Your model, which is that algae grown at one part of the tank cannot affect algae grown at another, is demonstrably wrong. It doesn't make sense physically.

That is not my model. The words I use matter, just like the words you use matter.

Again though, I've made careful distinctions that I'm not necessarily arguing in favor of ATSs, refugiums, or making claims as to the size/conditions that will be useful. But your argument that they can't work/haven't worked for others based on your model needs to be thrown out for the sake of science!

I am not making that arguement, and don't believe I have made that argument, here or anywhere else. I have also picked my words carefully, and those choices make a difference.

Another clarification, I'm trying not to mince my words here and am speaking very bluntly about the models for clarity of the discussion, but I'm not attacking you! I very much enjoy this discussion and think these scientific models can be difficult for people who are unfamiliar to get right away, so clarifications and more discussion is always welcome!

Thanks. I don't think you are attacking me, but I do think you are making arguments angainst positions I do not hold. Models like yours, though yours is really nice, have been around for a long time, however, in practice, the models don't reflect what we see happening a whole lot of the time in aquaria, as you seemed to be starting to understand in your previous post.

 

[Thales]

BTW, to put some context to the concept of competition. I performed tests in FW confirming that when organisms overpowered another that the other would be eliminated or minimized. This has been studied I'm sure. This is why I'm of the belief that same organism given a better environment in which to live will out-compete itself in less desirable circumstances. Just so many resources and why one able to consume it faster will survive while the other likely struggles. How all this impacts corals that I don't know yet however they do create their own energy and can be fed directly therefore perhaps the use of an ATS or Fuge to out-compete undesirables in the display could and should work without negatively affecting that we have decided should live for aesthetic reasons. Reefs full of algae that apparently get trimmed by tangs but not all can take that approach. My upcoming 15g cube will have me pursued by the tang police were I so foolish

Tangs are over hyped as the best herviror for tanks. People like fish because people like the idea that they can graze down long, or established algae - however tangs and rabbitfish rarely do that, fish like parrot fish do. Most herbivores that we keep won't touch long or established algae (some snails will sometimes). In small tanks (large ones too), tuxedo urchins, mexican turbo snails, trochus and other snails, as well as micro herbivores like gammarus, are good for dealing with algae after you have cropped it down so they can much on the smaller growth.