I agree it would be foolish to use 600's in those, they need the 1k's to overcome losses in the glass and coolant. Some say it's as much as 30% loss, I'm not sure if that's accurate but it does have to be significant because you're going through two extra layers of glass and the coolant.
I used to be into liquid cooled high resolution projector repair, and even precise lenses and the very best coolant in those did give visibly lower light output on screen versus the air cooled version of the same projector with everything else equal. Maybe 20% guessing.
FYI they used very pure ethylene glycol/glycerin as the coolant in a sealed system with lenses that cost around $3000. If you ever wanted to get a coolant that doesn't allow shit to grow in it, to make it more maintenance free and eliminate even further light losses from contaminants in the solution that's the stuff. 50/50 mix would do, and seal it up so no dust gets in. Once your system gathers any dust or other contaminates like algae or whatever efficiency will drop drastically. Tiny particles in the solution or that collects on the glass really play hell with passing light so you should do a serious full clean every cycle or more if just using water and not sealed, I'm sure you know that though.[/QUOTE
Ive put a lot of time into my research before i went and spend a lot of money into my set up. (sig) And it is no were near 20-30% loss even bout a light reader (
http://www.adorama.com/SKL358T.html?sid=1260259727661706 ) screwed around with it and figuered a few calculation i did with the reading from it to convert it into lumens. Gonna try to find all my old research and post it up here. i Believe i was only losing about 3-5k lumens off a 1000watt which has 125000 lumens. So im running 4 1000watt fresca sols which is 500,000 lumens minus the 20k s im still hitting 60 plants with 480,000 lumens and i can have the lights a LOT closer to the plants now so it is dam worth the sacrifice of those lumens.
just add chlorine to the rez with the water for the fresca sol. Auctually not chlorine as this does eat at the water nozzels on the refletors them self i use Pythoff (
http://www.4hydro.com/hydroponics/pythoff.asp )amazing stuff and eliminates all grow in the entire system and dosent eat at the water nozzels on the reflectors them selfs.