Growbed media's Biological Surface Area For Fishtank size

Calculate how small your growbed needs should be to be safe enough for your fish tank's size.

The ratio between the sizes of the Grow-bed and the Fish-tank depends on the biological surface area (BSA) of the Grow Bed. 

Aquaponics has 3 main steps:

1. Fish poo making ammonia. 
2. Bacteria colonies transform the ammonia into nitrite. 
3. Trees absorb nitrites to grow green leaves. 

The bacteria live on the BSA surfaces of the rocks which meet both air and fish water. So we control the amount of biological surface area so when the bacteria  colonize %100 of the BSA  the fish tank's toxic water is converted to healthy water. More rocks or more sand means more bacterial surface area. You can't have too much BSA, more the merrier, but it's toxic for fish to have not enough BSA.

The Calculator. 

This calculator works out the maximum size your fish tank can be for any type of growbed.
Media is the word used to talk about the rocks or the sand.

Instructions before you calculate:

1.  What's your fish tank's size?  Is your fish tank 130L? Then estimate 110L to 130L of fish-water.  plus the 1L water in the pipes and 20L grow bed. 
2.  Media is the rocks or stones used as the base of grow bed. 

Be aware that the growbed's media values are in meters, so 10 centimeters is written in as 0.1 ; and 155 centimeters is written in as 1.55 
And If you have separate containers, then add the container grow media volumes up (into cubic meters), and just put it in "growbed medium height" and make "Growbed Medium width = 1 and growbed Medium length =1 "  

Growbed's media height (meters)
Growbed's media width (meters)
Growbed's media length(meters)
If using 12mmPeaGravel, max-max size of fishtank (litres) =
If using 12mmPeaGravel, min-max size of fishtank(litres) =
PeaGravelwater inside growbed void, add to max above (litres)
If using 3mmSand, largest max size of fishtank(litres) =
If using 3mmSand, smallest max size of fishtank(litres) =
If using 25mmRocks, max size of fishtank(litres) =
If using 25mmRocks, min size of fishtank(litres) =

For each type of media there are two maximums: the smallest maximum which is the safe size; the largest max is when fish are in danger because there isn't enough BSA to make the dirty water clean.

   

From the calculator, the minimum size of a fishtank given the growbed's media is low due to 'void' between stones. The max size of the fishtank for a particular growbed media, is assuming there is no void (i.e: after a lot of settling down. )

So, now you have the scientifically verified way^[1] to create the grow-bed's base level of drain-rocks. And you can rest easy that it is likely your Aquaponics kit will be a successful blessing to the creatures living in it. 

[1].