ONLY BIOLOGICAL FILTRATION

[PuppyReef]

I've been thinking about setting up a reef tank using only biological filtration, without any mechanical or chemical filtration. Would this be difficult to achieve in an 8-gallon aquarium with just a wavemaker and heater? I haven't decided what I want to add yet, but I would appreciate any thoughts on this setup.

[geekreef_05]

I used to run skimmerless on reefs with no fish and light fish loads. Liverock was my primary filteration. The key is balancing your closed system and adjusting your water change schedule accordingly.

 

Its totally possible. 

 

I do recommend an HOB filter or basic mechanical filter of somekind to capture debris in the water column. It also provides a place for carbon, etc as needed. 

[mcarroll]

On 3/17/2024 at 1:58 PM, PuppyReef said:

I've been thinking about setting up a reef tank using only biological filtration, without any mechanical or chemical filtration.

Sounds like a "Berlin Method" setup....no traditional filtration, just high flow, good lighting, live rock and a protein skimmer.  Keep bio-load within the tank's limits and it's the easiest (and arguably the most successful) system to run.  

 

Adding a skimmer to the live rock (which is doing most of the heavy lifting) increases the potential total bio-load you can keep AND improves gas exchange for corals.  

 

Some folks also add activated carbon if they want to keep softies with stony corals.....softies do NOT play nice, chemically speaking.  Activated carbon can help.

[TheKleinReef]

I think it could be done, but it's so much easier to maintain stability with help from mechanical (skimmer, floss, socks, pads, etc) and chemical (carbon, gfo).

If i were to do it, i would probably set up an auto water change system and rely on that + macro algaes for nutrient export

 

flow would have to be pretty surface dominated to get the gas exchange since it's only 8g

[Sprinter70]

All my tanks are picos with only biological. The most important thing in my experience is to avoid introducing pests. Relying on corals as the particulate filtration leaves a lot of particulates in the water column for other pests. Arguably I am still learning my way but have struggled with aptasia, spirobid worms (not harmful to corals but can coat entire surfaces), and red planaria. Even hydrogen peroxide dips for preventing the introduction of pest algae would be beneficial. Introducing beneficial critters like micro bristles, asterina starfish (if you like em), and copepods are a must along with a “healthy” microbiome (I don’t know what this is or how to get it efficiently, but trust me, when you get it you will know, but before you do, things might not be too happy).

[fenderchamp]

My pico reef has been up for 3 years now with only live rock, light a heater and a powerhead and live rock.  I think if you are willing to change some water and maintain the tank you should have a pretty good chance of success.

 

My other aquarium has really thrived since about a year ago once  the same approach was taken.

 

light, powerhead, heater, bare bottom, live rock.

 

Pictures of  both tanks in journals.

[BadCrab]

I'd imagine the biggest thing you'll miss is the water polishing and surface skimming.  The tank might feel or look "oily" as a result.

[KC2020]

1 hour ago, BadCrab said:

I'd imagine the biggest thing you'll miss is the water polishing and surface skimming.  The tank might feel or look "oily" as a result.

+1 on the oily surface film.

Turn off your powerhead and when the water stops moving you'll see that multi-colored oil sheen on the water surface.

 

But yes, it will work just fine provided you change water weekly. As mcarroll pointed out, this is the Berlin method from yesteryear.