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Macroalgae Reactors – Should I Buy One?

I can’t remember a time when I didn’t keep macro algae. My first marine tank did not have a sump so I grew halimeda which is an attractive algae. Then I got a hang on refugium, and grew macro algae in it. Finally I got a sump and things took off from there. But, growing macro in your sump comes with problems. You have to have a light source for one, but that’s minor.

The real issue is that bits and pieces of the algae can sometimes come off and get sucked into your pump. For me the issue with that has been the pump getting clogged. I hate it when that happens. Another issue is that the algae can make it passed the pump and into the display tank. Though I have been lucky enough that this hasn’t been an issue for me, I’ve known people who end up with fast growing macro algae, like calerpa, in their main tank that they find hard to get rid of. Having a method to contain the algae in just one compartment of your sump solves this. There are a few ways you can do this, one of which is a macroalgae reactor. 

macro algae reactor

Before we get to just what that is there are a couple of other things you can do. First, you can simply put a screen up that blocks the algae from getting to the pump chamber in your sump. Or, as I do, you can place live rock between the chambers. Water gets through but the algae doesn’t. Remember, we’re talking about macroalgae so it stays put pretty well. For me, that rock method has been all I needed. 

Right now, I don’t have a macroalgae reactor. There are five reasons why not. 

  1. Cost – they are expensive. Depending on the size and brand $300 or $400 or more. 
  2. Work (harvesting) – Extracting algae from your refugium is simple. You grab some and pull it out. Harvesting algae is an essential part of growing it. With a reactor you have to take the reactor out, open it up, and then remove the algae. 
  3. More work (cleaning) – because the reactor draws water through the reactor you have to make sure that it remains clean. Failure to do so can make it so the reactor gets clogged. Flow is important to the growth of macro algae so if that happens it can result in die-off and the release of all those nutrients back into your tank. 
  4. More cost – You will eventually have to replace the lights and the pump in the reactor which will have it’s own cost. that is assuming the reactor is still made and those parts are available when you need them. Pick a reactor that uses universal pumps and lights and then you can be sure they will be available in the future. 

When I started writing this I thought that someday I really wanted to get a macroalgae reactor. Now that I get to this point, seeing the prices, pondering the logistics of it, and realizing that they are actually more work than algae in a sump, I now think the cost to benefit ration just isn’t there. They also limit the amount of algae you can grow compared to how much I could fit into an entire refugium chamber of my sump. Sometimes we get excited about the technology we can use and even just what makes our tanks look cool underneath but when we pause, we realize it’s not worth the money when it can be done simply using the good old fashioned, tried and true, techniques of reefing. 

chetomorpha macro algaes

There you have it, I started out wanting one of these, then ended up realizing it’s just not worth the cash. Maybe you have one and love it. I’d be interested to know. 

Tunze macro algae reactor

If you decide you do want one of these there is a good article you can read going over some top brands: The Best Macroalgae Reactors – Reef Builders Gear Guide | Reef Builders | The Reef and Saltwater Aquarium Blog

Let me know how you like it if you end up getting one.