I built a moving bed biofilter for my basement growout system.
This week I'm going to explain exactly how that works.
That's coming up.
Hey everyone.
Steve Poland here.
And this is the sixth part in a video series about the growout system I'm building for
my african cichlids in my basement crawlspace.
If you missed any of the previous parts there's a link down in the description to a playlist
to get you caught up.
An essential part of any aquarium is biological filtration.
It's what supports the beneficial bacteria that convert fish waste from ammonia into
nitrites and then ultimately into nitrates which can then be removed via water changes
or absorbed by plants.
When I was designing this system I knew that there were two qualities that I wanted in
a biofilter.
High capacity and low maintenance.
So I knew that a moving bed biofilter would be the way to go.
If you're not familiar with the concept of a moving bed filter, it's actually pretty
simple.
Any biofilter has to have a place for the bacteria to grow.
In a traditional filter that might be porous rock, ceramic rings, plastic balls, or even
foam.
In a moving bed filter, the most commonly used media is either sand, or what I'm going
to use, K1 Kaldnes.
Now this K1 media is a small piece of plastic that looks like a wagon wheel.
It was originally designed in Norway for use in municipal wastewater treatment systems.
There are a couple of benefits to this media.
First is its surface area.
K1 provides 800 square metres of surface area per cubic meter of media.
I bought a 50 liter bag, which is enough to handle up to 250 grams of fish food per day.
That's a lot.
Way more than I'll ever be feeding in this system.
The second big benefit to K1 is that it's self-cleaning media.
This was the biggest draw for me because like I said, I want this to be low maintenance.
The K1 will be constantly moving around the barrel.
This is acheived in a very simple way.
You just run an airline to the bottom and since the media is bouyant, as the bubbles
sweep up past it, it rotates it around.
And as this happens, the media bumps into itself.
The result is that the older, weaker bacteria are knocked off, leaving the younger, stronger
bacteria in place.
This greatly increases the efficiency of the filter and decreases the need for maintenance.
So to set this up I just needed a few things.
The barrel obviously, which I bought from a company here locally.
I also needed an air supply, which was easy.
I have a central air system in my basement fishroom and I've shown that in a previous
video.
I just ran a line over from that about 25 feet to the bottom of the barrel.
I drilled a hole in the side so that the lid could still sit flush.
At the end of the airline is a large circular airstone.
My K1 media I ordered from a pond supply company out in California because they had free shipping
But there are a number of places here in the US that sell it.
I then had one other thing that I wanted to add to this filter.
As I mentioned in the previous part of this video, my water flows out of my fish tanks
and into a radial flow filter.
This filter removes the large solids from the water.
But I still wanted a way to remove any smaller suspended solids that might make it through.
This isn't because I'm worried about water clarity.
That's not a concern in this system.
But in general you want the water that hits your biofilter to be as clean as possible.
So I came up with an easy solution.
I just bought a cheap little plastic bucket to hold some filter floss.
I drilled holes in the bottom, making sure that they were small enough that the K1 media
couldn't get stuck in them.
Then I drilled a two inch hole in the side of the bucket so that I could stick it over
my intake pipe.
This causes the water to hit the filter floss before draining out into the moving bed filter.
The rim of the bucket is high enough that it keeps the K1 out.
But it's low enough that worst case, if that bucket gets clogged, the water will just overflow
over the rim and down into the filter.
I'll have to change this filter floss periodically but that will be easy to do.
And that's my biofilter.
I think it will be great for this system.
And next week I'll be showing you the sump and how I put that together.
So be sure to check that out,
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Have a good one!