Yes, but in practice putting together than information into a useful "rule" would be an extremely difficult task, because in order to use it, you would have to know those specifics of every bulb you considered. It would almost have to be a spec that manufacturers provided.
Rather than urge them to provide that, I rather ask them to provide PAR values for say, 12" away from the bulb. This would be a useful number for comparing bulbs.
Yea, x2, the other thing, is that new bulbs are made every year and flood the market or new bulb technologies, such LED's, T5's reflector.
Most of the research on light uses PAR, there are trade offs for each method etc, cost, effectiveness, etc.......but the PAR meter is reasonable cost wise for a club to loan out.
No meter is really worth it to have for a single person.
Measure, do your test, then loan or rent it out, you will not likely use it much thereafter.
then you can compare folks's light for their plants at that time and in space. After all, the light changes as you get closer, and as we saw with the ADA lighting, it was much lower PAR than anyone had suspected.
So that type of info in much useful and predictive than watts/m^2 etc.
You would have never caught that using such rules and it does explain a lot when you look at dosing and CO2 demand etc. With less light, you can get away with a lot less. But if the light is not comparable, you add 2-3x as much light and wonder why it does not work/has lots of issues:silly:
All the folks that cried, whined, hooted and hollered over the last what? 20 some odd years about "light rules" and how to fix things never bothered to test it. Playing with silly conversion factors instead. Many of them harassed me about not testing NO3 via EI etc and suggesting people add non limiting nutrients ironically.
I know when and what to test for however.
This is classic case.
Reef folks got it, they spend lots of $ and time testing and measuring and doubting themselves. Not much with the plant folks' crowd.
When testing using a water proof probe like the Apogee, you can measure how light intensity changes through a week at the very tip of a stem.
This is interesting because you soon realize the plant is exposed to exponetially higher and higher light as it grows, then you trim it, and the prcoess starts again.
How does this light intensity change affect the system?
What does this do to CO2 demand?
NO3? PO4? demand?
Think it changes through time and space?
Now you have a tool that can get data and answer such things for light.
How does pruning affect light getting to the plants and how much should/do I do?
Now you can measure those things, measure all points in the aquarium, measure and compoare any bulb.
It would be nice to have a PUR meter that would give the units in terms of bioavailable light and what is used. They have such things but they measure light use indirectly for terrestrial plants.
They can measure bulbs etc with them and all, but they are not pactical or cost effective for us.
There are trade offs with every unit etc, but PAR weighs them all pretty well and is a good standard for aquarist and biologist both.
Regards,
Tom Barr
