Skimmerless reef tank

Going Skimmerless – An Experiment

For the last 4 weeks I have been running my 187 gallon reef tank without a skimmer as sort of an experiment. A few months ago I lost a number of corals due to what I believe were very low levels of phosphate in the tank. I run an ARID algae reactor and it does a great job pulling out nutrients. With the ARID you do have to dose nitrates to keep the chaeto growing and lately I have been dosing phosphates to keep levels from going too low. Ultimately, you want nitrates and phosphates at a 100:1 ratio to maximize chaeto growth. You can either use a skimmer or go skimmerless and let the ARID be the sole form of filtration. Ultimately, I decided to pull the plug on the skimmer.

Why I Went Skimmerless

I have been having some issues with cyano and I believe it might be due to excess C02 in the air where my sump and skimmer are located. The sump is in the same room as my furnace, a potential source of C02, and there is little to no ventilation in the room. In theory, shutting off the skimmer in this situation should lower C02 in the tank since the skimmer’s air intake will equalize C02 levels between the air and tank water. Cyano prefers high C02 so less is better.


At this point the cyano has receded a bit so my hope is that it will continue to do so. As I mentioned before, I have started to dose phosphates, another reason I shut the skimmer off since it was driving phosphate too low in conjunction with the ARID.

Currently, my nitrates are at 10 ppm and my phosphates, with the dosing, have climbed to .13 ppm, right at the 100:1 ratio I am seeking. However, I have increased the light period in the ARID to lower those levels with the hope it will help beat back the cyano even more. Stay tuned for future updates on my skimmerless experiment.

Additional Resources

If you would like some help with a new tank build, including help designing a custom aquarium, or help re-configuring your current setup then you can visit this page for more information. And if you are looking to add some equipment, I do sell GHL, Pax Bellum, Reef Octopus Calcium and Kalk Reactors and Royal Exclusiv products, including Dreamboxes, which is the equipment I use and recommend. I also sell Reef Brite metal halide and LED fixtures as well as Maxspect & IceCap Gyres.

As for additional insights and information, please explore my many other reef tank and SPS related articles as well as my YouTube channel. For an even deeper dive into reef tank care you can check out my Reef Keeping Master Class. This online course is an immersive and one of a kind educational tool designed to help reef aquarium hobbyists build and maintain a beautiful SPS reef tank. The course is a series of video presentations with some supplemental video from my YouTube channel. There are also quizzes to help students retain and understand the information presented in the course.

Need some frags…..I can help with that as well 🙂 Please visit my SPS Frag store to see what is available.

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