Here is the success or failure of your planted tank can happen.
There is a formula called “Watts Per Gallon”that can provide you how many watts of lights you need to grow most plants. Normally, 2.5 – 3Watt per gallon is sufficient to grow the majority of plants available that require “Moderate” light. However, this rule only applicable only if you are using standard aquarium sold by local fish shop. If you have a custom made tank (like my tank is 8inch taller), you need to add in extra light power.
Don’t know how to calculate your aquarium volume?
Try this >> Aquarium volume calculator
Note: This calculator is not EXACT your aquarium volume. When you add in gravel and rocks, water volume decrease.
To further explanation, i am using standard 2 feet aquarium as scenario.
So 2 feet aquarium has 24″x12″x12″ = 15gallon water. Requires approximately 45watt of light.
Let’s do some calculation, if you are using T8, 16W x 3 is good. Common casing only can fit 2 x t8. So you need 2 casing. You have to take care of the space on top of your aquarium as well, 2 casing will cover almost whole top of your aquarium?
Since Malaysia are using cm and liter unit, this formula might be more useful for those confused about feet and gallon.
To calculate light watt for your aquarium, use
Aquarium height (cm) x width (cm) x water depth (cm) / 1000 = light power
This formula is same as previous, using 1Watt per liter.
Example: 2feet aquarium has 60cm x 30cm x 30cm / 1000 = 54Watt light.
There are alternatives for light system in planted tank. Most common bulb used in planted tank would be T8, T5, T5HO, PLL, CFL, MH and LED. Some bulb output high density of light but also great heat is generated. So cooling system like DIY fan must be install to cold down water temperature. Different bulb also has different life span. Kindly refer to shopkeepers before you decide which kind to buy.
2feet aquarium, 24inch x 12inch x 12inch, 15gallon water, 45 Watt light
3feet aquarium, 36inch x 18inch x 18inch, 50gallon water, 150 Watt light
4feet aquarium, 48inch x 18inch x 18inch, 67gallon water, 201 Watt light
Thanks for reading! 🙂