1 more lighting thread with some questions
 

So I need some opinions.
On my 90g mainly sps now tank(48x18x24) I have 2 Iwasaki's mounted aprox 12" above the water surface.

Can any of you see any benifits to adding a 175 w 10000k bulb inbetween the existing iwasaki's?

My other thought is because of the crossover of light across the tank would the corals in the center or middle 36"(aprox) be the only ones to benefit from the added light?
What I mean by this is if one of my halides is on and the other is off the light crosses over more than half the distance of the tank.

Any thoughts on this??
Thanks All :D

you mentioned that your brace is made of acrylic now.. that might be a problem with the MH right over it.. might soften it and cause it to fail..

I can't see that you would even notice it against a couple of iwasakis.. it might brighten up the middle a little bit.. but if you wanted a even look throw an aditional iwasaki in the middle :wink:

Steve

Well I figure at 12" above the brace it wont be much of a problem.

My whole idea behind this was to increase the light a little in my tank and maybe get a bit better color out of the sps.???

Anyone else???? or is this just a crazy Idea?
Yes part of my reason for doing this is all the other areas of my tank are fully tinkered and I NEED another project to work on. :? :lol:

Some old dead guy once experimented with light and water. Much was learned and it's all really boring. Two points come to mind that in part answer your question. First of all at the boundry between light and water a portion of the light is reflected. The amount that is reflected can be calculated using the sin of the angle of incidence ( or something like it). Basically the amount of light that enters the water is decreased as the angel increases. When light enters the water directly below it very little is reflected and can be said to be more intense.

The next most boring thing is what happens to the intensity of the light as it passes throught water. If I recall the intensity drops by about 50% in the first 10 cm's, and then much more slowly afer that (60% at 20 cm to 30% at 40cm).

So adding a light in the middle of the two existing would increase the intensity across the tank, and especially directly below it. So if this is what you wanted to do...

Here's an idea: for your next project, build a simple piggy-bank. Label it "Radium 400s" and start dropping your tinkering funds into it. Much better. :)

Alan :D

That's a great Idea Alan! I have allready started that fund saving in my amarula tin!

I think this is what I was ultimatly thinking to do but we will see.

Thanks ross for the info. It was rather boring though :wink:

That's funny, I kind of have that same project going right now, except that I keep raiding the piggy bank for other things .... like .... Christmas presents ....

rossb is sooooooo right, I grow orchids, betcha didn't guess that. While searching for a MH for my room I was very very suprised to find out how quickly light intensity drops off. When a MH bulb is rated for say 40,000lumens, that is how much light is thrown over a 1sqft area 1 foot away from the bulb. At two feet the light will have approx, 1/2 of the intensity, at 3 feet, 1/4, at 4 feet, 1/9th... that is in air, remember water is alot denser than air so ..... anyway.... ross is right, if you can afford the $$$ I would add the other light, just make sure you keep an eye on that brace and see how hot it gets.

Thanks Orchid guys!

I think I may do it. I basically have all the part except the socket and reflector. So it's not going to be too much to add it, another $75 for a socket and reflector + of course the electricity each month but when it's as high as it is I dont worry to much any more. :roll:

In the mean time I will save up for the radiums :wink:

You can always move to BC, electricity is 5 cents/Kwh here... at least in Burnaby it is.