You picked the one photo which shows, in my eyes, a too generous use of the filtermat. Usually, one tries to construct a quarter-circle, and the picture above looks more like an egg or ellipse. ;-)
I tried to do a calculation for some typical tank sizes, so you can see how much ground surface of a tank is used for a HMF (corner construction)
L W H are the lenght, width and height of the tank in [cm]
Area [cm2] is the surface area of the tank
Area HMF [cm2] classical construction : The recommended size of the mat according to calculations for HMF where the mat is a the left/right end of the tank, stretching from front to back.
radius mat [cm], the recommended radius for the mat, if built in a cornered way
area bent mat [cm2]: the surface area of the mat if constructed that way and stretching from ground to water surface. VERY close to the results two colums left
space req, for HMF [cm2]: how much area is used for the tank, when seen from above,
% of total space: how much of the total surface area of the tank is used by the tank
Interpretation:
In small tanks (like the 63 liters =17USG) a HMF in the cornered construction uses 1,1 % of the bottom area of this tank. This percentage increases with tank size.
What to learn of it: In small tanks you will have to build your HMF with a larger radius, otherwise a 5cm radius is too small to place a pump/heater behind and such a small radius bends the mat too much. In larger tanks (> 80Gals) it is recommendable to build two in each corner, preventing an all too large filter in one corner.
The area behind the mat: It's used usually for the heaters, the CO2 reactor, the pH-electrodes, a bag of peat for watertreatment. Usually no extra filtermaterial.
When you want to do you own calculations you will need the formula for the circumference and the area of a circle.
Hope that helps.
Jörg
I tried to do a calculation for some typical tank sizes, so you can see how much ground surface of a tank is used for a HMF (corner construction)
L W H are the lenght, width and height of the tank in [cm]
Area [cm2] is the surface area of the tank
Area HMF [cm2] classical construction : The recommended size of the mat according to calculations for HMF where the mat is a the left/right end of the tank, stretching from front to back.
radius mat [cm], the recommended radius for the mat, if built in a cornered way
area bent mat [cm2]: the surface area of the mat if constructed that way and stretching from ground to water surface. VERY close to the results two colums left
space req, for HMF [cm2]: how much area is used for the tank, when seen from above,
% of total space: how much of the total surface area of the tank is used by the tank
Interpretation:
In small tanks (like the 63 liters =17USG) a HMF in the cornered construction uses 1,1 % of the bottom area of this tank. This percentage increases with tank size.
What to learn of it: In small tanks you will have to build your HMF with a larger radius, otherwise a 5cm radius is too small to place a pump/heater behind and such a small radius bends the mat too much. In larger tanks (> 80Gals) it is recommendable to build two in each corner, preventing an all too large filter in one corner.
The area behind the mat: It's used usually for the heaters, the CO2 reactor, the pH-electrodes, a bag of peat for watertreatment. Usually no extra filtermaterial.
When you want to do you own calculations you will need the formula for the circumference and the area of a circle.
Hope that helps.
Jörg