How much PAR is enough?

[moonpod]

Actually in my experience the 20K DE's after a few month (Both Coralvue and PFO) look more like 12-14K. I would not go as far as to say it's a stability issue since all bulbs have a burn in period where the bulb temp alters. The bulb temp of my 400W de's did not change after about 150 hrs of run time. (of course this is limited to the interpretation of my eyes and the reasponse from the life in my tank, which is good)

Well it's all in interpretation. If you get your 20k bulb and understand that it's gonna be pretty much a white bulb, not blue after a few months and you're ok with that, then I guess it isn't a bulb stability issue. Ditto the 10k and it being yellow instead of white.

I guess the thing that really gets me with the 400w DE was that the testing of at least the happyreefing and icecap units by Joshi wasn't all that impressive vs the Lumenarc or vs the 250w DE reflector testing.

 

[jlehigh]

Correct, they are not as blue as most 20K's. 400 DE's are not light years of a difference but they are the most efficient solution if you don't want to run actinics in addition to MH. The Spread is also quite good. Anyway this is a tangent off the thread but I appreciate your comments.

 

[Boomer]

MikeS this may be a more liking to to much light

Too Much Light!
http://www.advancedaquarist.com/issues/july2004/feature.htm