What is the tank size? That is a lot of light for a long time for most common tank sizes.
Hoppy, I definitely agree with you on this point. However, in my opinion, low light tanks that have a large fish load, and where the majority of plants are root feeders (and the plants are fed as such), then the need for water-column phosphorus can be low enough that it isn't necessary to add (although it doesn't hurt!).I'm not sure that fish poop is a good enough source of phosphorous for any but low light tanks. Since excess phosphorous does no harm I think it is always a good idea to be dosing it. The lack of phosphorous can bring plant growth to a virtual halt, no matter how much of the other nutrients are present.