No prob Steph, I have always said that the Iwasaki is a bright bulb but you always want to compare apples with oranges [img]smile.gif[/img] if you want to compare a 10K bulb... compare it against another 10K bulb. Or got out and get a 6500K DE and use that. The iwasaki bulb is not a satandard bulb in the sence that it puts out way more light than even bulbs of the same color temp this makes it not a good bulb to base a comparason on as it is a exception not the standard. If you look at other 250 watt MH bulbs they are all less that 1/2 the out put of the Iwasaki it is the same as trying to compare a 6500K PC against a 10000K PC, the 6500K will have more PAR but the 10000K looks better.
Now if we go with the numbers Sanjay got from his test is was 140PPFD/PAR for the 250 iwasaki and 128.8 PPFD/PAR for a Ushio 10000K HQI NOT a AB DE as you stated. in fact the 110 you reported for the AB was for a normal AB 10000K MH bulb not a DE HQI.
The AB DE bulbs are to HQI, like the Iwasaki bulbs are to normal MH bulbs.. I don't know if that made any sence but after talking with AB and my family in Germany that use the AB (and for some time now) that is the impression I am left with. Still at 180.00 cdn for a 150 watt bulb and god knows how much for a 250 watt bulb they are way out of my reach so I think I will settle for a 250 watt Ushio 10000K HQI sence they have almost as much out put as a Iwasaki with out the yellow IMO.
here is the link for the down and dirty data :D
you will find that there were only 2 HQI bulbs tested the first was the AB 150 DE HQI (tested with reflector and glass) the second was a Ushio 10000K HQI DE tested bare.
TEST RESULTS IN A NICE TABLE
when Darren posted his pic's of his tank with the iwasaki and the 10000K bulb on it I liked the 10000K bulb better, from the pictures there wasn't much difference in brightness but if you look closly his corals are floressing a little harder under the 10000K.
The one thing I like about the idea of using a DE bulbs is that by varing the thickness of the glass under it you can controle how much UV is entering your tank, this way if UV is a large contrubiting factor to the color of corals you will be able to find that perfect balance by using different thickness glass.
Steve
[ 08 June 2002, 00:56: Message edited by: StirCrazy ]