Too much light??

[StirCrazy]

Originally Posted by Canadian

Also note that the upper values of measured PAR in this study were around 1100 which are readily achieved in a typical aquarium with 2 x 250W MH:

where did you find this in the article?

If they were getting PAR that high from anything under a 1000w bulb, they were holding the sensor 2 to 4" from the bulb.

the highest output bulbs I have tested so far were SE AB 10K's running on a magnetic M80 ballast, at 12" of water and air (7" air and 5" of water) they were putting out just shy of 700, at a depth of 23" water and 7" of air they were putting out about 480 to 500. I have tested 4 400 watt setups and various other 250 watt (both DE and SE) and none have come close to these numbers except the 400 watt iwasakis, which were about 20 points lower.

Bulb testing the way it is done on the bigger boards is stupid and useless to us as it reports theoretical numbers, not what you will actually get. So yes I could see theoretically the ability to supply to much light, but in reality I don't think you or me will do it. I am going to have my bulbs more than 1" above the waters surface and I am going to have my corals more than 1" under the surface. If they happen to grow to the point where these is to much light then they will simply stop rising and spread out instead. come to think of it I had a digitata do this in my old tank, grew to about 1" under the water surface then tabled out. was beautiful, but it never slowed in growth and I would be willing to be its growth could have been measured in oz/day. but at any rate I don't believe it is something we have to worry about in a practical application.

Now lets stop scarring everyone from adding to the discussion, if we want to keep going back and forth we should get a coffee

Steve