Watts per gallon out the window...

The irony of this is right before I got into reefs I was working for an independent testing laboratory. A light testing lab! We had more testing equipment there than you could think of.

I also has access to people who could build ballasts and wire up all the halides my little heart could desire.

 

Problem with watts/per linear foot or square inch or anything else using watts will always be skewed.. Case in point, 65w PC lamp over a tank as compared to a 54 watt T5 is a no brainer, T5 would win... Take LED... OR lets say you have a 1000w MH lamp W/O a relfector over the tank... A 400w with reflector and maybe even a 250 would compete with the 1000watter...

Watts is simply a measure of energy used... Don't care if its good ole Doc Foster and Smith still telling people they need xyz watts per gal, its wrong regardless if its sq/ft sq/in or whathave you..

Also Ocean, Quatum(PAR) meters are more like upper $300s for a Apogee or ~$1000s for a Li Cor...

Most people do not want to drop that money to simply test amount of PAR...

 

Wrap your mind's around this:

Bulb: 6700K 96 Watt compact fluorescent PC96W67K
Watts: 96
Max Lumens: 29100
Rated Lumens: 8100
Efficiency: 0.28
PAR uE/s: 117
PAReff uE/s/watt: 1.22
PUR total uE/s: 56.1
PUR Blue uE/s: 27
PUR Red uE/s:16.7

Compare those numbers to these:

Bulb: Iwasaki 6500K metal halide
Watts: 150
Max Lumens: 37700
Rated Lumens: 12000
Efficiency: .23
PAR uE/s: 199
PAReff uE/s/watt: 1.33
PUR Total uE/s: 107
PUR Blue uE/s: 46.6
PUR Red uE/s: 35.2



These are the important numbers here:

PC Bulb
PAReff uE/s/watt: 1.22

MH Bulb
PAReff uE/s/watt: 1.33

That doesn't seem like the huge jump I would expect between MH and PC bulbs.

Lets say we had one of both these bulbs running at 100 watts. MH would give off 133 PAR and the PC bulb would give off 122 PAR.

Judging by these numbers and the fact that I kept SPS and anemones under PC lighting for over a year I'm beginning to wonder why lighting companies have convinced us the more expensive lighting works better.

If anyone could supply one I would love some kind of explanation.

All my number's were found here:
Aqua Botanic-light bulb comparison

 

Notice you posted this on another thread... I would say that it is incorrect info per the other thread(for those that did not read other thread)

 

WPG really doesn't matter when it comes to MH...

you can have a 70w MH and put it in a 300g tank you can put an SPS near the surface and it'll grow fine...

the rest of the tank will be dark but you can grow SPS with 70w.

WPG really only applies to fluoros, and then its still not the best measure, but it's a good convention for getting a basic sense of minimum light requirements.