# Algae Scrubber theory question



## Bubba Shrimp (May 7, 2012)

I don't deal with algae I have 3 Bristlenose Plecos


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## Gold Finger (Oct 13, 2011)

Bubba Shrimp said:


> I don't deal with algae I have 3 Bristlenose Plecos


They attack your fish?


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## steven p (Jun 22, 2012)

Bn's are not too aggressive, more defensive. Algae does seem to stay away from my plants when they have some wood or rocks too grow on.. 

Regardless, I think eventually the scrubber would win unless you were using massive ammounts of ferts.


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## Gold Finger (Oct 13, 2011)

steven p said:


> Bn's are not too aggressive, more defensive. Algae does seem to stay away from my plants when they have some wood or rocks too grow on..
> 
> Regardless, I think eventually the scrubber would win unless you were using massive ammounts of ferts.


If you go to goldfish or discus forums you will find thousands of post of people who were surprised when the BN plecos they had for years suddenly started attacking their fish. Sometimes you get away with it, sometimes you don't. People theorize as to why, but if you read enough posts you begin to see that it's a crap shoot.


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## dprais1 (Sep 12, 2012)

there is a forum somewhere on algae scrubbers where the creators and sellers of algae scrubbers swear up and down that they work great for freshwater tanks! 

Then there are all the people with freshwater tanks that don't seem to see the results promised.

I'm guessing part of the reason is the temp of the lighting used in planted tanks vs non-planted tanks

At least that was what I got out of the forum, for saltwater sounds like it works, but saltwater tanks are designed different by necessity.


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## Gold Finger (Oct 13, 2011)

dprais1 said:


> there is a forum somewhere on algae scrubbers where the creators and sellers of algae scrubbers swear up and down that they work great for freshwater tanks!
> 
> Then there are all the people with freshwater tanks that don't seem to see the results promised.
> 
> ...


 Yeah, I bet most of the folks sellin 'em are saying they do some stuff they likely don't. They can wipe out nitrate which is why they work in salt. I want to know how they behave in fresh. I don't get your reference to temps, by the way.


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## plantbrain (Dec 15, 2003)

They work well by adding a lot more light in the ATS vs the aquarium.
If you add lots of light to both locations, they are the same then.

So they do not eliminate algae per se.

They remove nutrients, but plant filters/emergent plants are FAR more effective and a simpler device. Reef folks have macro algae, the grasses and trees do not remove like the FW emergent plants. 

Floating water sprite etc, or a peace lily in a wet/dry section will out perform any algae filter with less energy.

"Hydrophyte" has several simple hand on or suction cup planters that would do the job if you want to keep it simple.


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## Gold Finger (Oct 13, 2011)

plantbrain said:


> They work well by adding a lot more light in the ATS vs the aquarium.
> If you add lots of light to both locations, they are the same then.
> 
> So they do not eliminate algae per se.
> ...


Thanks, that makes sense. Not a magic bullet for tank algae. End of that question. 

I have experienced how well plant filters work and agree they are more simple than a modern ATS, but I am working on a new design which is very, very simple, and as for plant filters being far more effective at removing nutrients I hope to be able to narrow that margin quite a bit with my design. Microalgae, after all, are the fastest growing "plants" of all. They can double their mass in under 12 hours! I really enjoy plant filters but am finding growing algae to be a lot of fun too. My fish enjoy the bonus O2 injection provided which is one reason I am giving ATS a try. Also, I like to screw around with stuff.


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## dprais1 (Sep 12, 2012)

The big draw for freshwater tanks is removal of nitrate, plants are the only reason you would want nitrate in a tank that I know of.

Temps-I was referring to temp of lighting. I imagine 6500-6700 grows algae best, so if you have temps at extremes your fish might look better but algae wouldn't grow as well. In planted tanks well we often create algae factories


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## Gold Finger (Oct 13, 2011)

dprais1 said:


> The big draw for freshwater tanks is removal of nitrate, plants are the only reason you would want nitrate in a tank that I know of.
> 
> Temps-I was referring to temp of lighting. I imagine 6500-6700 grows algae best, so if you have temps at extremes your fish might look better but algae wouldn't grow as well. In planted tanks well we often create algae factories


OOOOh, Kelvin temps! I get it.


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## plantbrain (Dec 15, 2003)

Gold Finger said:


> Thanks, that makes sense. Not a magic bullet for tank algae. End of that question.
> 
> I have experienced how well plant filters work and agree they are more simple than a modern ATS, but I am working on a new design which is very, very simple, and as for plant filters being far more effective at removing nutrients I hope to be able to narrow that margin quite a bit with my design. Microalgae, after all, are the fastest growing "plants" of all. They can double their mass in under 12 hours! I really enjoy plant filters but am finding growing algae to be a lot of fun too. My fish enjoy the bonus O2 injection provided which is one reason I am giving ATS a try. Also, I like to screw around with stuff.


You are beating a dead horse.
Algae actually has very little biomass relative to plants per unit area.
So you can doble that biomass in a short time frame, but the expect is still next to nothing relative to a plant, say duckweed which can double every few days, Azolla can also. But as the plants and algae grow at exponential rates, they become quickly limited by other factors and by space, self shading, low O2 levels due to respiration during the dark cycles etc etc.

Theory is one thing, reality is quite another.
then there's management of the ATS and export vs grabbing a handful of weeds and then selling them here on TPT.

I sold 250$ worth of plants this week.
When you sell 1/10th of this, 25$ for your algae, come talk to me.

In lakes, most of the biomass is algae because there's often not much plant biomass. You can design all you want, but the algae require more flow and mixing, and more light to even come remotely close, and those 2 things in artificial culture requires more energy. You have to manage this puppy also.

Aquatic plants for wastewater treatment. See Reddy and Smith, 1984,

ATS' are better at removing and maintaining very low ppb's ranges.
At higher nutrients, plants are better. Think about it like this : Elephants and mice are both herbivores that like grasses. Which can handle a low grass biomass area over time? Mice. An elephant can eat a lot more though when there's an ample food supply. 

That's one somewhat imperfect analogy, but you get the point.

For planted tanks, we add NO3, we are not concerned about maintaining ultra low NO3 levels. Unless you raise cold water trout etc, no real reason to go this route. Non CO2 planted tanks tend to have N limiting conditions. 

For reefs, where there is little input and export, they are quite useful. 
Still, I'd say the Zooxanthellae like a little bit, not much, but a little N and P to color up and do well and a decent skimmer can get rid of other stuff.

I've used ATS in the past before getting into plants, and the plant filters got more and more interested.

But then why have a plant filter at all? Just make the entire scape and tank itself the filter.

Export is plant cuttings which you can give or sell. Inputs? I add nutrients, I'm not trying to export them, I'm trying to keep the levels up to help the plants grow.

Fish? I've bred maybe 50 species in planted tanks over the years.

Well, go ahead and play with the ATS's, but you'll need t prove these things to yourself over time. I had to and thought many of the same and similar things myself back in the day.:thumbsup:

Cannot fault anyone for that, least I'd have to slap myself for doing it too:icon_cool

BTW, algae are not limited by nutrients in planted tanks.


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## Gold Finger (Oct 13, 2011)

$25 for my algae huh? I was thinkin' a bit more than that but "what the heck". I'll get back to you when I've sold some.

Thanks again. I'll check out Reddy and Smith and focus on those limiting factors you mentioned.


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## Gold Finger (Oct 13, 2011)

plantbrain said:


> You are beating a dead horse.
> Algae actually has very little biomass relative to plants per unit area.
> So you can doble that biomass in a short time frame, but the expect is still next to nothing relative to a plant, say duckweed which can double every few days, Azolla can also. But as the plants and algae grow at exponential rates, they become quickly limited by other factors and by space, self shading, low O2 levels due to respiration during the dark cycles etc etc.
> 
> ...


Tom's post really nailed all of the factors which I have to contend with in my scrubber desing and have helped me create an excellent scrubber which I would put up against any plant scrubber. (thank you Tom, if you see this) I will get back to him directly when I have sold some algae for $25, which I am now convinced that I will do. I will certainly not be the first to sell established algae filter screens . Meanwhile I am posting my thoughts here for my own benefit and for any interested onlookers. 

First I want to say that there is no doubt that a tank full of healthy plants is a wonderfully eloquent and effective solution to the algae issue and the best filter of all... but only for those who want this end result. There are those like me who want big dirty plant destroying fish which won't get along with masses of beautiful plants. We want all the plants we can have but we have chosen a fish-first aquarium which does need a scrubber. No one thinks these things belong on a plant-first tank.

That being said I have come to believe that the algae horse is far from dead. My first experiments put plants and algae head to head and the plants won. I now know this happened because i PUT BIG healthy plants up against algae starting at the invisible spore stage. If I had put young plants up against established algae the algae would have won. Both plants and algae export nutrients very well and trying to determine which one exports more is very hard to do. It is apples and oranges. The factor which makes algae a better candidate for a scrubber is reliability. Plant filters need steady levels of nutrients and other factors to keep from getting out of whack and getting covered in algae, but algae filters adapt to fluctuating conditions and don't get covered in plants when conditions are less than perfect. They bounce right back. I think this is why the big tanks at marineland use algae scrubbers and not plant scrubbers, and maybe it is why more and more reefers are trying out algae scrubbers over plant scrubbers. I think Tom is right in implying that algae scrubbers need more designing and better design. I also think I have come up with such a design. I am writing a patent application and testing prototypes so I can't disclose it yet.


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## Gold Finger (Oct 13, 2011)

To put it more simply, Plants do well in healthy balanced aquariums while algae do well in unbalanced aquariums, and an aquarium which needs a scrubber like a fish only aquarium or an aquarium which has insufficient plants is an unbalanced aquarium. These tanks will support algae scrubbers with dependable results, but not plant scrubbers... not in the long term without tinkering. It reflects the natural scenario.


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## Rooi (Jan 5, 2020)

Thank you all for clearly explaining the benefits and shortfall of algae scrubbers.

As it seems a new tank might benefit from an algae scrubber and an established planted tank with plant eating fish might equally benefit.


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