Merits of refugiums for nano reefs?


New member
This is a "why" rather than a "how-to" question...

I can use the limited space at the back of our 28g nano for either an upgraded HOB skimmer, or a HOB refugium. A lot of nano folks seem to go for the latter, but I'm a little skeptical of the water treatment benefits. (I don't care too much about growing more copepods. )

Is a 2 gallon refugium (my calculation of the amount of water a converted power filter will hold) filled with macroalgae and sediment, with a water change rate of more than 100+ gpm (based on the filter literature) really effective in improving a 20-30 gallon system's water chemistry?

I couldn't find any articles with actual data for systems of this size, so any opinions/experiences/or especially studies would be much appreciated!


Randy Holmes-Farley

Reef Chemist
Premium Member
The benefit of growing macroalgae is in related to the amount you feed the tank, since it is the nutrients from foods that you typically want to export.

So a 2 gallon refugium on a 28 gallon tank (with appropriate lighting) may be just as useful as a 20 gallon refugium on a 280 gallon tank.

That said, my refugia have more surface area than do my main tanks, as well as pretty intense lighting for growing macroalgae. I think that if you want refugia to be a primary export method, you may need proportions on that order.


New member
Thanks Randy! The concept of a 20 refugium for a 280 gallon system seems less realistic to me than 2:28.

I'd be interested if anyone else has an opinion, since there seem to be a -lot- of HOB 'fuges out there. Not that I'll take it more seriously than I do Randy's. ;)
I run a 50 gallon fuge on a 30 gallon tank. I made the fuge a display because i enjoy studying that as much as the main display!


Salty Dude
Premium Member
I have an 8 gallon nano at work. The middle section growes cheato. ZERO nitrates.