Backyard Aquaponics
A place to discuss aquaponics

Hi
An ad on the back of a Koi magazine caught my eye.

K1 Micro ( Bio-filter Media) 950m2 per m3
Ok.. Is that good very good or what?

Another way of looking at it. 1 m3 = 6m2 surface area.
So 950/6 =158.3 ( Sorry Stuart, only 2 places of decimals)
An efficiency of 158 to 1
Another ad in another mag for ‘Bio-balls’ .......21-1/2 square ft
Now I am assuming they mean ft3
So 42 ft2 per ft3 (no need to convert to metric)
42/6 = An efficiency of 7 ?
Something is is wrong.
Is it me?
My maths?
Help!
Titus

Where did you get this figure from


It depends. If you are really short of space then its better than gravel as a biofilter by a factor of ~3*. If you are not short on space then maybe not because it is a lot more than three times as expensive. It depends.

* Rough gravel has a ratio of ~300m2/m3 smoth gravel less scoria a lot more.

Hi
A cube has 6 sides
Ie 1 m3 has 6 m2
Titus

So
Rough gravel an EFF of 50
Titus

it all comes down to how much surface area you can cram into a small area, and that area (surface area) be colonized by bacteria. I to would say it all depends on what you are doing, so 900+m2 surface area is a lot of area for bacteria to colonize but if your bio load (fish load) is a max of 10kg it is over kill and a wast of space and would be difficult to get it to work properly I would think from my experience as you would have to take a few things into account like wast load, flow rate and total volume, I'm not saying it wouldn't work, I think it would but it could be like having ten fish in a swimming pool (say 20000ltrs) with .5m3 grow bed, it may work to some degree? but it wont be optimal.

there is lots of info on bio filters so keep looking.

Also from one of your other posts doesn't your system have gravel beds anyway?

If my memory is working right then in order for your system to be stable so that there is room to store and process the solids then you will have more than enough gravel for bio filtration.

Hi
Thank you Stuart and Grunta

Two points.
I would like to have 50 fish in my system. At 250 gm harvest size 12.5 k.
At 3kg per 100 ltr media I should have 450 lt I have 340 ltr So 110 short.
However when split and running as two independent systems I have 260 ltrs in one but only 80 ltrs in the other. A shortfall of 170 ltrs. So I need a bio-filter equivalent to 170 ltrs of F&D media.
This leads me on to the second and main point.
When you start reading about bio-filters everybody talks in different units.
Some talk about volume of water processed. Others weight of K1 or K3. No of bio-balls etc and most use different comparisons.
K1 at 950m2 / m3 is logical. (Bio balls at 21-1/2 square ft is just advertising gobbledegook)
Yet another claims 1 ltr of K1 will clear 5 grms of food per day. 12.5 k fish @ 2% food 25 grm/day so 5 ltrs K1 equals 450 ltrs F&D media.
Help.
What I am clumsily trying to create is a simple comparison.
Titus

Yeah you have to compare apples with apples.

The last example you gave of 5g of food per day would only be valid for fish food of a certain protein content.

Not being familiar with your system I ask why do you care?

Calculations on biofilter size and capacity are generally not done in AP systems BYAP systems in particular because generally there is enough surface area in growing media, plants roots and the like to ensure that there is more than enough surface area to ensure bio filtration is taking place. Generally solids processing capacity is what limits you stocking density.

Granted there has been a large increase in the number of systems that are using standard koi or aquaculture components but that seems to be because people generally don't understand media based AP systems and how stable and reliable they are if they are stocked and operated appropriately.