Puzzled About Lighting Levels

[Underwurlde]

Yep simple it is.... But the watts per Gallon rule does not take into account the footprint of the tank nor indeed the depth - for your 80 Gal it should be OK though, as the footprint is pretty standard and it is not more than 48" deep.

The Watts per Gallon general rule applies to fluorescent Watts, with reflectors, per US Gallon.

Note also that different types of bulb T5, T8, T12 etc also have differing efficiencies. (Consider also that a T5 is smaller diameter and hence more of the reflected light would get past it than a T12).

For your 80 US Gallon tank, I would suggest a minimum of 4 x 40W fluorescent tubes up there and hence a minimum of at least 50% to 75% planting.

Andy

 

[George Farmer]

Here's a very basic guide to lighting levels that works well for most tank sizes -

Assuming the lighting is full-spectrum with good reflectors spanning the length of the tank

T8

Very low - 1 tube
Low to med - 2 tubes
Med - high - 3 tubes
High - v. high - 4 tubes+

HO T5

Low - 1 tube
Med - 2 tubes
High-v.high - 3 tubes+

PC T5 (compact fluorescent)

Low-med - 1 tube
med-high - 2 tubes
v.high - 3 tubes+

You could grow most species with med-high providing you have good CO2 and other nutrients. V.high levels I'd recommend for experienced growers as the algae risk is greater.

 

[mnew]

It looks then I could do with a second 40W tube for my tank. More wires ! To think my first tank had two 60 w bulbs and I used to remove the plants from time to time so I could see the fish !