DIY Algae Reactor by Reef Giants

Were you Googling, “How To Make Your Own DIY Algae Reactor”? Well, you came to the right place if you are seeking a step-by-step guide on how to do just that. Now, if you’re like me, then you love the reef tank hobby, but aren’t convinced that the people setting those “market competitive” prices on tank equipment are all that right in the head. There are many components we reefers need that don’t even have any electronic or moving parts, yet somehow they cost an arm and a leg. Take a look at sumps for example…what makes a box with some plastic dividers, cheap rubber and a logo worth $450? The price of this glorified Tupperware that someone drilled a few holes must have a decimal out of place. No thanks…

DIY Algae Reactor meme making fun of unreasonably high priced aquarium equipment

So, that leads me to the topic of today’s post – the sub-$120 DIY Algae Reactor! You can Do-It-Yourself, and while the steps below look long and somewhat tedious, they are not difficult. In short, needed a way to reduce my nitrates as well as increase my Copepods population and add a biological filter to my system. Since I have a traditional thin-glass aquarium (no drilled holes), I wasn’t fond of the idea of trying to add a sump to my system, since I that meant having to drain the tank, drill holes in the glass (only a 1/4 inch thick, mind you), hook everything back up and hope that the glass wouldn’t crack (likely while I am at work, and my wife would get stuck cleaning up the flood – and me? Never to be seen or heard of again!). Hmm…also going to take a hard pass on this option as well. However, I still had a problem I needed to solve – HIGH NITRATES!

For a while, my tank had been running on average at 15ppm for Nitrates. This is not egregious, but still not good long-term for fish health; much less invertebrates when I start adding those. I knew I needed a solution, but one that didn’t break the bank.

I was talking to @bkurtz about this issue, and he mentioned he gotten the Tunze Algae Reactor, which seems to be the go-to for reef hobbyist looking to add one to their system. Brian loved it, and I wanted the same results he was reporting, lower nitrates and a copepod bloom (*salivating*), but I could not accept the $340+tax price tag. I studied it for a few hours, and watched some YouTube videos, and it looked like a simple enough machine such that I could construct on my own…that planted the seed for this post, so let’s dive into the journey! I’ll go over the itemized parts list and prices, as well as provide links to the source where I got them; then we’ll discuss how to actually get it hooked up and working. All in all, the parts cost me under $95, and if you include the starter algae then that’s another $20. This build and implementation takes about 3 hours from build-start to having your DIY Algae Reactor up and running!

Materials List:

Build Procedure/Steps: (click images to enlarge)

  1. Assemble the Somatic UF-1 Reactor (this is very self explanatory if you just look at the images below; all parts and connectors you need come in the Reactor box). Note: Do NOT use the red circular sponges that come with the Reactor. They will decrease the effectiveness of your DIY Algae Reactor, so leave them out.
  2. Cut two lengths of tubing (same length for both) to fit your needs: the length of each tubing should be the height from floor to top of your tank + the height of only the tank itself. For me this ended up being 70 inches per tube.
  3. Attach both segments of tubing to the Reactor outlets (red connectors)
  4. Connect the tube coming from the center Reactor outlet elbow, to the Pump (this is the hose that will pull water out of the tank and force it into the Reactor)
  5. Connect the tube coming from the offset/side Reactor outlet elbow, to nothing (this should be left open-ended as this is the return hose that will push water back into the tank). Note: The recommended tubing’s ID (inner-diameter) of 1/2″ is slightly smaller than the connectors – I did this INTENTIONALLY. It will take some elbow grease and determination to get them attached to the Reactor’s red-colored connectors; however once done, this will ensure a watertight seal without the need for additional clamps, rubber gaskets or messy epoxy.
  6. Move the connected tubing and pump out of the way, then starting with either end (both of mine were wired, so it didn’t matter), wrap the LED light strip around the outside of the reactor in a spiral fashion, with the rubbery LED side facing INWARD (the strip will move around a bit because it is not secured, that is ok right now). Note: Theoretically, a tighter coil will bombard the algae with more light, and thus cause faster growth; however, I prefer a looser coil as there’s only ‘so much’ light that the target chaeto can absorb in the given space.
  7. When you have the coil in place, put a small piece of tape at each end to temporarily hold down the strip, and remove the self-stick adhesive protection paper.
  8. Cut the end that has excess, if you have any (I did). Be sure to cut where indicated, halfway through the periodic metal leads.
  9. Rotate your Reactor slowly, and examine your LED strip’s slope as it spirals around the Reactor. Use your finger and thumb to scoot/nudge areas of the spiral into place to fix spacing issues, or move slack to one end or the other as needed to be sure the light will have even distribution across the height of the Reactor chamber.
  10. Once you are satisfied with the LED strip pathway, use the Clear Gorilla tape to secure the LED strip to the exterior plastic wall of the Reactor, keeping the LED strip centered in the width of the Gorilla tape as your wind the tape from one end to the other. Once the tape is in place, you should flatten it down to be sure it’s secured well. Note: Applying the tape can be tricky unless you have four hands, so I recommend another person help you hold the Reactor and rotate it slowly, while you apply the tape in an even spiral, centering on the LED strip pathway and matching its slope as you go.
  11. Strip the red and black wires at least a half-inch (if needed) and connect then to the green power adapter. Note: Be sure to TEST the LED strip here to make sure it lights up, before going any further. (I guess we should have tested it before we did all this work, but I guess I trusted it would be fine). When this turns on, you’ll feel an amazing sense of accomplishment (at least I did, making the past hour or two or work all worth it).
  12. Ensure the white LED strip wiring sheath is covering the end of the strip properly, then wrap the entire wiring assembly (from end of your LED strip, all the way to end of the power adapter) using black Gorilla tape (you can cut smaller/slimmer pieces here if that makes it easier/prettier)
  13. Wrap the first 12-18 inches of tubing connected to the top Reactor outlets (both hoses), with black Gorilla tape. Note: The purpose of this step is to blackout the tubing that is in close proximity to the Reactor’s LED light strip, so that algae doesn’t grow inside the pathway, clogging your setup. This COMPLETES the build process for your new algae reactor!
DIY Algae Reactor completed setup
Pictured above: The completed DIY Algae Reactor

Tank Integration & Implementation Steps:

  1. Move the completed DIY Algae Reactor to your tank area and using a clean cup, manually transfer some tank water into your reactor until it is about half full.
  2. Place the Clean Chaeto (starter algae) into your reactor, and seal the lid.
  3. Place the submersible pump, with the hose running from the pump to the center Reactor outlet/elbow into your tank directly, or into your sump somewhere out of the way (e.g. in a back corner)
  4. Place the other tubing (return hose) down into the tank and arrange it on the bottom, such that it will not force it’s way out (e.g. I lodged mine under a bit of my aquascaping/rocks so it is weighted down)
  5. Turn on the pump, and observe it for 5-10 minutes. As you observe it, check each connector at the pump, and on top of the Reactor outlets/elbows. You may need to perform some minor wiggle tests to ensure things are tight. Add the Gorilla tape if needed on any of the hosing near the reactor. If you have leaks, then something is wrong, or not fully secured. Note: If needed, use the clamps that came with the Somatic UF-1 Reactor kit to keep the rubber elbows and red tubing adapters secured together. See below for my initial setup where I placed my Reactor in a 5-gallon bucket with a towel in the bottom so I could easily observe any leaks that occurred (none did after initial setup and hasn’t for the week it has been running, so I am fortunate).

Note: @bkurtz clued me into a tip regarding the LED light schedule. While the pump runs all the time, you will want to run your LED light on a schedule, typically opposite your tank light. For example, if you have your main tank light turn on at 7am and off at 7pm, then reverse that for your algae light (on at 7pm, off at 7am). I also suggest that you place your Reactor in an enclosed space below your tank, and not anywhere the Reactor LED light could shine into your tank. The purpose of this is to keep algae growth in the Reactor and not have it occur in you tank directly.

Best of luck and success in creating your own DIY Algae Reactor that is just as effective as the commercial ones, but at a fraction of the price! Feel free to leave a comment below on how this guide helped you, or how it might be improved based on any roadblocks or different context you ran into. What questions do you have? What insights to help make us better? Comment below or catch us on Instagram and slide into our DMs yo… See ya there!

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