View Full Version : Chaeto Reactors compared to Algae Scrubbers

09/17/2017, 03:47 PM
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 me know.

09/20/2017, 08:51 PM
Any more information coming? I've been toying with the idea of an algae reactor of some sort to potentially help combat low ph. I'd love to know more about the potential pH impact of algae scrubbers/reactors.

09/20/2017, 09:17 PM
Yes am writing it now. The pH factor though is not a major feature; it's more of a nice side effect.

09/21/2017, 12:11 PM
I love my Algae Reactor. All I have in there is Chaeto at the moment but it's working very well. So well infact, I had to reduce my photoperiod as my corals were starting to pale. Im coming from running ULNS with ZEOvit and I'd like to stay away from that low of nutrients. I will say, I've never felt so naturally in control of my nutrients nor have I had such vibrant colors.

09/24/2017, 11:39 AM
I have a question, how big does a chaeto reactor have to be in order for it to be effective in removing nutrients?

09/24/2017, 06:02 PM
So well infact, I had to reduce my photoperiod as my corals were starting to pale.

That kinda sucks, I hate reducing viewing time.

Or better yet, maybe reduce your light intensity and raise the photo period back up.

Just my 2cents.

09/24/2017, 09:23 PM
For size, that will be detailed soon. I'll be adding DIY cost too.

09/25/2017, 01:49 PM
My vote is for an ATS. I have a 10"x9" lit with 40 3 W red.

Great algae growth. I deed the equivalent of 8 frozen cubes. Also have carbon dosing.

09/25/2017, 09:42 PM

09/27/2017, 12:12 PM
Just harvested 361 grams from my waterfall ATS. (5 days)

09/28/2017, 06:30 PM
That kinda sucks, I hate reducing viewing time.

Or better yet, maybe reduce your light intensity and raise the photo period back up.

Just my 2cents.

Just a heads up, I reduced the photoperiod of my Chaeto Reactor, not my Display :D.

09/28/2017, 08:32 PM
Absent scientifically valid test data on nutrient uptake of an ATS versus chaeto reactor, it's all just anecdotal opinion, frankly. Always wondered where the cubes-per-day sizing of the ATS came from because my own experience is that the sizing isn't accurate at all. I see little material difference between chaeto grown in a cannister versus a refugium. Certainly a refugium can serve multiple purposes, but that doesn't invalidate it as a space in which to grow algae. I run a 144 sq inch, double side lit ATS and two large refugia. One solely for the purpose of growing chaeto and one as a refuge for animals that would otherwise perish in my main tank (what a novel concept :)).

09/28/2017, 10:43 PM
The cube size thing came from me, after watching tanks with various sizes and feedings.

Back in the day, people tried to build 3 x 3 foot screens above a 20g tank, almost like a sail boat. They never grew or filled in. So the cube sizing get them started on the right path.

09/29/2017, 06:23 AM
Back in the day, people tried to build 3 x 3 foot screens above a 20g tank, almost like a sail boat. They never grew or filled in. So the cube sizing get them started on the right path.

Well, maybe so. I built my first ATS based on William Adey's book (right when it came out, 1995 maybe; don't recall exactly). It worked fine, though messy and noisy .... and a space hog. Dump bucket 'driven' and only lit from above (by mercury vapor lamps). Revised to an early version of a waterfall not long after which worked much better. I've had refugia on my system for a long time, though mostly as a place to house animals that were getting harassed in the main display. Only started using chaeto for nutrient removal about 5 years ago. I have found that the ability to grow chaeto in a system that already uses an ATS is not about macro nutrients, but more about things like iron. Thus I dose, judiciously, in my system.

10/19/2017, 08:58 PM
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.

10/20/2017, 10:54 AM

Have you seen the cryptic zone thread in this forum? Do you have any thoughts on the research referenced there showing different levels of DOC production by turf algae versus Chaeto or other macro algae?

You're describing algae as the "filterer" in nature. What about cryptic zone biomass, or bacterial biomass, which can also potentially uptake the same nutrients?

How about the differences in effect on bacterial populations for turf algae versus cryptic zone biomass, given their different effect on DOC in the water column? Again, there's research on this referenced in the other thread.

10/20/2017, 11:13 AM
Initially I had my waterfall ATS running with chaeto underneath. ATS was hands down out competing my chaeto. At some point I feel like I hit a wall where the growth wasn't impressive for either. Sine then I have significantly upgraded my lights for both ATS and chaeto, as well as started iodine and carbon dosing. At this stage I would say they are neck and neck with growth, and the growth is absolutely incredible. I feed like a crazy person, and my display is clean of all nuisance algae.
I am not a fan of running GFO in a reactor and find this method to meet all my needs and keep my water relatively pristine.

10/20/2017, 01:01 PM
Have seen lots of cryptic and other studies, and am a fan of Tyree's early systems too. But as Shia posts, I'm more interested here is covering practical usable stuff.

The definition of filtering I'm using is the formation of living material from non-living, i.e., the opposite of re-mineraliztion. In most of the earth this is only done by algae (photoautotrophs). Cryptic zones don't do this. And the DOC's from algae, including carbs, vitamin C, amino acids, etc, are a nice addition to the filtering but not really the focus.