I have created simple “Light Calculation Chart” using simple formulas in MS Excel (I am no computer buff) which might be helpful to fledgling planted tank hobbyist. I wish to share the same with you all.
I have divided the light intensities into 5 categories taking the Lumen per Square Inch (LSI) at the middle depth of the tank. These categories are:-
1. Low Lit – The light will only be sufficient for slow growing low light plants like anubias, java fern, and moss.
2. Medium Lit – The light is sufficient for growing common undemanding aquatic plants.
3. Well Lit – The light is good for all except the difficult demanding aquatic plants. CO2 is not a must in this category but you will find good response if you use it.
4. Bright Lit – CO2 becomes a must and you are free to grow whatever you fancy.
5. Very High Lit – Sky is the limit here as long you don’t evaporate your tank. CO2, Fertilisers and frequent trimming of the plants will enslave you in this category.
I have done away with the ancient Watts per Gallon regime but only for the sake of old times will show it in the results.
Download this chart and save it before using it:
In the tank Volume just type in the white spaces the Length, Height, and Width in inches of the tank you want to find out about. Make sure that the measurement of height is the mean height of water column above the substrate. (if you have the measurement in cm then you can find out the same in inches using the conversion table)
In the total lumen installed chart just type in the white spaces the total wattage used against the type of bulb on the left.
In the reflector chart just choose the type of reflector used by typing 1 in the white space on the right of the reflector type.
Now just scroll down and see the result against the Unknown tank.
You can use the chart to find out about your present tank or plan for your future tank.