I found those numbers on differents sites so maybe the setup and technique for mesuring wasnt exactly the same but it gives an idea

USHIO 400w 20000k
Ballast - Power - Input Volts - Input Amp - PPFD
Standard (M59) - 451 - 118.3 - 4.13 - 109.9
Pulse Start - 445 - 118.5 - 4.20 - 102
PFO-HQI - 486 - 119.5 - 5.75 - 112.0
HQI-Taiwan - 450 - 120.1 - 4.05 - 106.5


Radium 400w 20000k
Ballast Voltage (V) Input Current (A) (Watts) Lamp Voltage PPFD
Magnetic 120 - 3.75 - 398 - 124.6 - 90.63
PFO-HQI 120 - 4.53 - 439 - 128.0 - 110.2
Blueline 120 - 3.67 - 408 - 124.7 - 114.4

does that state what the PPFD was bassed on? Ie. distance ans what medium it was measured through?

Steve

The numbers for the Ushio bulb came from an article fromAdvanced Aquarist Magazine and are based on Sanjay Joshi spectral analysis... And for the Radium they also came form an analysis from Sanjai Joshi so the circumstance of the analysis should be similar ?????

I have the setup and both bulb to do the test, but d'ont have the instrumentation to do it :cry: :evil:

I see some people claim that the Radium and Ushio 20k are the same bulb..

http://reefcentral.com/forums/showth...hreadid=234520

they are both blue bulb and not 20 k but people in the industry call them 20k butt no they are not the same bulb and look totaly different inside and outside

I try a radium 20k on a agro ballast beside a hushio 20k on a m59 ballast on my reef they both look very nice

the radium is brighter and less blue but is give less fluorescence to coral

I have to admit I have found the hushio very very nice color even nicer than the radium

for the intensity I found the hushio more dim with the eye but have not tested with any meter

By the way the hushio dont have a blue glass

Ushio?
:razz:

Maybe Hushio is the "whisper quiet" model..