[StirCrazy]

Originally Posted by TheReefGeek

Steve, a question for you.

I know say 6500K iwasaki bulbs have great PAR, but do you know how much of that PAR gets to the bottom of a 30" tank compared to a 20K bulb? .

a lot more than the 20K bulb.. just because the PAR is higher to start with and 2 feet of water isn't going to make a difference.

Originally Posted by TheReefGeek

The blue in the 20K should penetrate better, but I don't know whether 30" will make a difference or not?.

In 80 feet of water nope.. what you got to under stand is that the blue is not filtered out as fast as other colors of light.. so think of it this way .. even a 6500K iwasaki has a huge blue component to its spectrum.. that blue will make it just as far if not farther than the radiums or XM's 20K as it is more intense to start with.. now talking about our 24" tanks.. doesn't matter not going to cut out enuf to be significant.

Originally Posted by TheReefGeek

And lower K is not always higher PAR. 20K XM bulbs put out more PAR than 15K XM bulbs, just wanted to point that out.

Is this a new 20K bulb as the old test results showed that the 15K put out more.. but at any rate.. 15K and 20 are not accurate there 20K is probably about 17K and there 15K is probably about 16K in reality.

a AB 10K has an actual color of 13.6K and will blow any bulb on the market out of the water if run properly.. so don't get all hung up on K values as for the most part it is a misleading number used for marketing.. I had one companies bulbs here a 10K, a 14K and a 20K.. the 10K was a very impressive bulb with a decent look and a very high PAR output. the 14 and 20K bulbs you could not tell the difference in by looking at them but a camera could pick it up.. very slight.. I would say 500K to 1000K real life difference at most. but they were also both about 1/2 the Par of the 10K at the bottom of my tank so 24" of water plus 8" of air.

personaly I would like to get ahold of one of each of these new bulbs and run some par test like I did a coupld years back but I am not in the finantual position to blow 600.00 on bulbs I don't need. Now if anyone wants to loan or donate some different bulbs we can do some used comparasons on aged bulbs and see how different bulbs hold up.

also just because a bulb looks blue don't assume it has a higher blue output than a bulb that looks crisp white.. that crisp white bulb is usually a high (very high) blue spike, with just enuf green and red to make it look white.

but we shoudl leave Bob's thread to his Nano and continue this in a new thread of you want to discuss more on this.


Steve