Fluorescent T5 , T8 and other tube coral growing colour functions.

This link first up is the inner workings of the tube.
http://www.eere.energy.gov/basics/buildings/images/fluorescent_tube_lamp.gif

The electrode to the left as is on both ends internally are what ionises the gas with the help of the fittings starters that fires bursts of electricity to enable this function.
You see a 4 foot fluoro tube light uses a small amount of voltage like 22volts or there about, the ballast takes out most of the current.

All this happens in the tube to make light that flows through the varied coloured phosphorus powder coatings to give these lights their colours.
These colours stimulate photosynthesis and makes corals and other common algae grow in a reef aquarium.
In time the heat given of by résistance lighting is what ruins these powders capacity to provide adequate colours to enable adequate photosynthesis.

These photos show the powder coating.

Fully coated in side the tube with the varied phosphorus powders.


A slight finger rub in the powder coating.


The small area rubbed away of its coating.


The powder has been washed out to near the end of the tube.