To make a long story short I stumbled across this simple method to calculate light requirements. As of now I can't say for sure how accurate it is but I'm about to find out. Using this formula my light's should be almost perfect for an 11hr lights on day.

**The Formula:**

When calculating the amount of lighting you will need there is a general of thumb. First multiply the surface area of the aquarium by the distance from the light source to the top of the gravel. Then depending on the type of plants you desire multiply this by one of the factors given below.

Low light plants 0.08

Low to Moderate light plants 0.12

Moderate to Bright light plants 0.18

Bright light plants 0.27

This will give you the ideal watt hours of fluorescent lighting that you need. Divide this number by 11 and you now have the approximate total wattage of lights you need. Unfortunately this number may not be equal to what is available in bulbs so find the combination of wattage that will most closely match this requirement and adjust the available time to match the watt hour calculation.

*Example*: required watt hours is 1440, divided by 11, is 131 watts of power. since the closest is 3, 40 watt tubes we divide 1440, by the 120 watt total and we find we need 12 hours of lighting at this level.

*Warning*: A common mistake is to deviate greatly from the 11 hours of light to compensate for low or high wattage. If the light time exceeds 16 hours more wattage should be added to reduce this time, Or if the light time is less than 8 hours less wattage must be used to allow adequate time for photosynthesis.

When selecting plants also keep in mind that large center plants will shade the smaller plants under them and that higher light requiring plants should not be selected for small filler plants.