Chaeto Reactors compared to Algae Scrubbers

SantaMonica

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#1
With more people wanting to use natural filtration for their tanks, we are going to look at the two main types of units that you can put on your system: Chaeto reactors (or "algae reactors") and algae turf scrubbers (ATS). We won’t be looking at refugiums however, since those have mostly a different purpose. This will be a multi-part post; the next post will start with the basics, so if you’d like anything in particular to be covered, let us know.
 
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SantaMonica

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#5
Chaeto Reactors compared to Algae Scrubbers, part 1

All macroalgae operate basically the same, chemically. They all use light, photosynthetically, to absorb nutrients from the water (i.e., filtering) and to grow biomass. Just like trees. The differences between types of macroalgae are in the physical structure of the macroalgae growth and the way the structure affects nutrient absorption speed, which means filtering. Here are the main differences as far as aquarists are concerned:

Chaeto: Pronounced KAY-toe. Chaeto is the nickname for Chaetomorpha, and it looks like a green dishwasher cleaning pad. It has no "roots" and thus does not attach to solid surfaces. It grows in saltwater only, and is not eaten by many fish.

Green Hair Algae: Includes Cladophora "angel hair" and Ulva "Easter basket" types. It has "roots" which attach to solid surfaces. It grows in freshwater and saltwater, and is eaten by almost all herbivores.

Slime: A solid algal growth, bright green to brown to black in color, that attaches to solid surfaces but not very securely.

Chaeto Reactor: A device that has water running through it, with chaeto growing in it. Also known as an "algae reactor". A chaeto reactor does not allow air to enter; only water, and these reactors usually have a lid attached with screws to keep water in and air out.

Algae Scrubber: Also called a Turf Scrubber, or Algal Turf Scrubber (ATS). A device that allows air and water to interact to create a turbulent air/water interface like waves on a beach; it grows green hair algae or slime that attaches to solid surfaces.

Reactors and scrubbers are different from refugiums; a refugium (“fuge”) is a space in a sump where macroalgae is placed, and a light is put over it. Refugiums have very slow flow, and very low light penetration, compared to reactors or scrubbers. You could modify a refugium to be a reactor, and with more mods you could make it a scrubber. But then it would no longer be a refugium.

All oceans, reefs, lakes and rivers are naturally filtered by photosynthesis. This means that algae does all the filtering of these waters. This is why algae is at the base of the entire aquatic food chain, and why algae biomass dwarfs the biomass of all aquatic animals combined. But for algae to absorb nutrients out of the water, the algae must grow. And to absorb nutrients faster, the algae must grow faster.

Next we will look at what makes different types of macroalgae absorb nutrients differently.
 
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#6
Off to a good start. Hope I'm not high jacking thread. I personally don't get algae reactors. Not big enough to really achieve any nutrient export even though it seems they grow algae quick. You're having to remove it more often thus adding to the maintainence of system which most already complain about. I'd copy and post a thread I just read on refugiums that stated most if not all are under sized and improperly set up making them ineffective thus people look for alternatives, thus the reactor was born. Reason for doing a search is I'm looking to redo my baffless sump with nothing more than live rock and skimmer. All I had on my last tank unless you count the little box in the upper corner a fuge or reactor. Manually dosed 2 part and nothing more. Hope link works. Just realized after watching video again. Where's all my fish? This was after I had a fish die off period. Was losing a fish about every other day and never knew why. That birds nest looks funny because I dropped a rock on it. Many frags of corals on sand bed. Remember my wife and kid crying when they came home and saw a guy and his buddy loading it up. I kind of want to cry now looking at it.
http://s874.photobucket.com/user/dd...s[user]=98298497&filters[recent]=1&sort=1&o=0
 

ddien

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#8
I stopped running an ATS scrubber since I still had algae growing all over the rocks in the display tank. Furthermore, I read on other forums that such a high concentration of algae in an area means they're releasing spores back into the water and that may lead to algae blooms in the display tank waiting to happen.
Perhaps you'll address this in the thread later down the line.
 
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#9
How long did you run your ATS? They're not overnight sensations. And what clean up crew do you have. Everything on a tank is part of integral system. If everything worked like ChemiClean this hobby would be easy. I for one had an ATS only tank and never had a problem with algae in the display. Ran without water changes for about two years till I sold set up. Actually had two tanks set up with them. The second one did fine for about a year then I struggled with after moving contents into another tank. Ran fine till the switch. Tried them again on other tanks without desired results. Couldn't get screen to take off. May have been a low nutrient problem as I tend to neglect sometimes and count on fish living off of what's in the tank. I for fact know they work. Just not all the time for me. But fact is people struggle with skimmers and other types of filtration all the time.
 

theMerchant

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#10
I run a algae scrubber and my display is algae free. The scrubber provides the concentrated light source that allows the algae to out compete for nutrients (thats why I want it for in the first place) . My nitrates and phos are ultra low and I may need to reduce the light cycle to feed my sps.
I spent the extra money and bought one from Santa Monica, even though Im an avid DIYer because I wanted it to be robust. The LED light source on the Rain2 is custom made, you can see the 3d printer was hard at work, Combined with the support I received I think its well spent.
I didnt want the traditional water fall type since in my opinion will have allot of light bleed causing the sump to have algae. With the Rain2 its pretty cool to keep all the red light inside. My sump is pretty clean as well.
If your still getting algae after running a scrubber , then its most likely not setup correctly.
 

SantaMonica

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#11
I personally don't get algae reactors. Not big enough to really achieve any nutrient export even though it seems they grow algae quick.
Well the quick part is key, and I'll cover that later. Size is secondary.

How does a scrubber completely contain hair algae?
If you mean what I think, a scrubber does it by have the best conditions inside it for growth, thus the algae does not grow (or grows less, or dies) outside the scrubber.

I stopped running an ATS scrubber since I still had algae growing all over the rocks in the display tank.
Sounds like the scrubber may have been working so good that phosphate was coming out of the rock; see below.

such a high concentration of algae in an area means they're releasing spores back into the water and that may lead to algae blooms in the display
Not true at all. Algae spores/cells/seeds/etc are everywhere at all times, but they only grow where they have the best conditions. Like just cold/flu cells.

Phosphate flow out of rocks:

Many people, when they get their scrubber running for the first time, get worried when more (not less) algae starts to grow on their rocks. It seems really strange, especially when nitrate and phosphate tests have been lower than before. What is happening is that phosphate is coming out of the rocks. Remember, phosphate is invisible, so you can only see the effects of it, and it always "flows" from higher concentrations to lower concentrations (just like heat does).

Example: If your room is warm, and you put a cold object on the floor, heat from the air in the room will "flow" into the object until the object and the air are the same temperature. Example 2: If you put a hot object on the floor, heat will "flow" out of the object and go into the air in the room, again, until the air and the object are the same temperature. Now suppose you open your windows (in the winter). The warm air in your room will go out the windows, and it will get colder in the room. The object on the floor is now warmer than the air, so heat will flow out of the object and into the air, and then out the window.

Think of phosphate as the heat, and your rocks as the object, and your windows as the scrubber. As the scrubber pulls phosphate out of the water, the phosphate level in the water drops. Now, since the phosphate level in the water is lower than the phosphate level in the rocks, phosphate flows from the rocks into the water, and then from the water into the scrubber. This continues until the phosphate levels in the rocks and water are level again. And remember, you can't see this invisible flow. It's like a fast flowing, but shallow, river. And it can be much more phosphate than how much you are feeding each day.

This flow causes an interesting thing to happen. As the phosphate comes out of the rocks, it then becomes available to feed algae as soon as the phosphate reaches the surface of the rocks where there is light. So, since the surface of the rocks is rough and has light, it starts growing MORE algae there (not less) as the phosphate comes out of the rocks. This is a pretty amazing thing to see for the first time, because if you did not know what was happening you would probably think that the algae in the scrubber was leaking out and attaching to your rocks. Here are the signs of phosphate coming out of the rocks:

1. The rocks are older, and have slowly developed algae problems in the past year.

2. The scrubber is new, maybe only a few months old, and has recently started to grow a lot; possibly dark and thick.

3. Nitrate and phosphate measurements in the water are low, usually the lowest they have been in a long time.

4. Green hair algae (not brown) on the rocks has increased in certain spots, usually on corners and protrusions at the top.

5. The glass has not needed cleaning as much.


Since skimmers, filter socks, etc don't remove any nitrate and phosphate, and waterchanges and macro's in a fuge don't remove much either, most people have never seen the effects of large amounts of phosphate coming out of the rocks quickly. But sure enough, it can with a scrubber. How long does it continue? For 2 months to 6 months, depending on how much phosphate is in the rocks, how strong your scrubber(s) is, and how many other phosphate-removing filters you have (GFO, carbon dosing, etc). But one day you will see patches of white rock that were covered in green hair the day before; this is a sure sign that the algae are losing their phosphate supply from the rocks and can no longer hold on. Now it's just a matter of days before the rocks are clear.
 

SantaMonica

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#12
Chaeto Reactors compared to Algae Scrubbers, part 2

By Santa Monica Filtration

Now for some basic differences; more detailed differences will be in subsequent posts.

The first and maybe most important difference is that chaeto reactors grow only in saltwater (fish only, or fish with live rock, or reef) whereas algae scrubbers grow (filter) in both saltwater and freshwater. Growing = filtering. But even if you are exclusively freshwater, understanding the differences between reactors and scrubbers enables you to optimize a system for your tank. There have not been any experiments of chaeto in brackish water however.

A second difference is size; a chaeto reactor needs to be much larger than an algae scrubber. Many saltwater tanks have large sumps, and even dedicated fish rooms, so this may not be an issue. Through experiential results of individual aquarists running chaeto reactors over the last few years, and through many thousands of aquarists running algae scrubbers over the last ten years, it has been observed that a chaeto reactor needs to be 4 to 8 times the physical size of an algae scrubber to provide the same rate of filtering capacity (rate of nutrient removal).

A third difference is seeding; a chaeto reactor needs to be seeded with a small amount of chaeto, either from another aquarium, reactor, or from your last harvest (i.e., you don’t harvest all of it), whereas an algae scrubber will self-seed from invisible algal cells in the water. When self-seeding, algae scrubbers usually start out with a slime type of growth, and this sometimes progresses on to a green hair algae growth, depending on the nutrients in the water.

A fourth difference is in how you clean (harvest). For a chaeto reactor, you disassemble the reactor usually by unscrewing several screws on the top of the container, and then by pulling out a tube or frame from the container; the chaeto growth is then removed from the frame and the frame is replaced back into the container, and the lid and screws are put back into place. Since chaeto does not attach to a surface, you often get broken chaeto pieces that flow into your tank or sump when you harvest; a filter screen in the reactor can reduce this.

For an algae scrubber, cleaning (harvesting) varies on what design it is; freshwater versions will usually be taken to a sink for the cleaning because of the thin and slimy growth (saltwater versions can also be cleaned in a sink, but are sometimes harvested in-place). A horizontal river design will have a light that you lift up off of the container, and a screen that you remove from the container. A waterfall design will have a screen that you remove from a pipe; sometimes the whole pipe is removed, and sometimes the pipe is in a container that you need to open first. A bubble upflow design has at least part of the container under water, which you lift out of the water. And for all algae scrubbers, since the growth is attached to a surface, broken floating algae pieces are not common when you harvest on a proper schedule. Bubble upflow scrubbers almost never detach because the growth is supported by the water.

A fifth difference is fish feeding; by feeding your fish from the growth, the fish eat naturally and you don’t have to buy and add food to the water (which creates nutrients). Very few if any aquarium animals eat chaeto, so the only option is to remove the chaeto and either throw it away or give it to a friend. For algae scrubbers, it depends on the growth: Slime (although full of absorbed nutrients from the water) is usually not eaten by aquarium fish and thus is scraped off and thrown away or used as garden fertilizer. Green hair algae however is eaten by almost all herbivore fish and many snails (it’s their nature food), and thus some of the growth can be fed back to the fish, especially in freshwater where algae scrubbers almost always grow this type of growth.

A sixth difference is overgrowth of algae on the lights. Chaeto reactors usually have a large surface area light (such as a long coiled light strip), and the illumination from these is not enough to “burn” off algae growth on the surface of the clear wall (this growth reduces illumination output). So you will need to clean these glass surfaces in order to keep the illumination at full output. Most algae scrubbers however use discrete (separate) high power LEDs which produce enough illumination in a small space to burn off algal growth on glass surfaces; for these you do not need to wipe the growth off because it does not grow there.

A last difference is overgrowth of algae on the algae itself. Chaeto is a slow growing species of algae because of it’s thick cellular structure, and if conditions favor faster growing algae you will get green hair algae which attaches on top of the chaeto, causing the chaeto to be blocked from light and flow, and eventually causing the chaeto to die and rot. There is no easy way to wipe green hair algae from chaeto; the chaeto must just be harvested earlier instead. For algae scrubbers, green hair algal growth on top of more green hair growth is how scrubbers operate in the first place, so earlier harvesting is not needed.
 

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