Wow

[Texreefer]

:hypnotyized: I keep my 400 watters about 18 inches above the tank and that is where my VHO's have been as well just out of convenience(never could spell that word). Well, I finally got off my Duff and devised a way to lower them to around 4 inches off the water:bigsmile:. I cannot beleive the difference in just two days. The colors are just popping!@!!!!!!!!!..
I Know, I know,, how can i post this and not post pics, but it is well documented by me that i have neither the camera or the talent to take a good pic, anyone with a good camera is welcome to come by the house and stand up and testify to the power of par baby!!:shades:

[urban79]

Your VHO or MH?

[erikharrison]

I have been wondering about the effect of PAR ratings through that dull space of air between the light and water. I guess going from 18" to 4" would be of great difference as is though!

[BIGBIRD123]

Mike you still want that Miami Orchid? If not, LMK.

Steve

[apedroza]

Let's see some pics!!!!

[Texreefer]

the MH stayed at 18" just the VHO moved down

[ou812pezz]

Funny you should mention this. When I stopped by to pick up the cap and you mentioned lowering the lights made the colors pop but you had problems with the heat. On my way home, I thought if you made a motorized light rack(pulleys and a slow motor to wind and unwind a cable) that would lower and raise on a timer that would solve your heat problem. I'd be interested on how you finally went about it.

[Texreefer]

I used highly advanced technology............bungy cords:bigsmile:

[MRSBIGBIRD123]

Need to see pix, so my husband can do that with his.

cheri

[Richard]

I have been wondering about the effect of PAR ratings through that dull space of air between the light and water. I guess going from 18" to 4" would be of great difference as is though!


No need to wonder about it. Physics has already figured it out. It's called the inverse square law. A simple way to look at it for what we care about is...

(far distance/near distance) squared = brightness

So for Mike... (18 / 4) squared = 20.25. So by lowering the lights to 4 inches from 18 you increased the light intensity at the water surface by 20.25 times.

[LoneStar]

No need to wonder about it. Physics has already figured it out. It's called the inverse square law. A simple way to look at it for what we care about is...

(far distance/near distance) squared = brightness

So for Mike... (18 / 4) squared = 20.25. So by lowering the lights to 4 inches from 18 you increased the light intensity at the water surface by 20.25 times.

Thats why you should stay in school kids :)

[erikharrison]

Thats why you should stay in school kids :)

:) Richard thanks so much for that information, now I am going to run around my house, lower my lights to 4" above my head run that equation on every light replaced, and I will report back in a diligent well-written DIY!! :P

[RayAllen]

Elementary my Dear Watson, elementary,lol. This is really interesting, but ive always run my lights 4-5" from the waters surface, with that said ive never run MH only Pc and VHO. Very Cool thread

[Bill S]

Richard -

Well sort of. Your math assumes that the bulb is an open bulb with no reflector - and no surrounding walls (white or otherwise) to reflect the light.

If you have an enclosed canopy, you will only lose light these ways:

Thru the side of your tank (put mirrors on your tank!)

From radiation heating - basicially, the heating of the surrounding items (walls, reflector, water, rock, fish) by ineffecient reflection of the light (that's why the sun makes you warm - skin doesn't reflect well...).

[hobogato]

dont forget that that equation is for a light sorce that is a point, not a long tube. i remember reading somewhere that long flourescent tubes dont follow that rule exactly because they are not a point light source like a metal halide.

[Richard]

A simple way to look at it

I did say that.

What I hated about physics was that the laws are pretty simple but then you get the test and had to do 5 pages of calculations just to get to the point where you could apply the law. Make one mistake along the way and you fail the test. Still the laws of physics always apply (even in maast land LOL).

Reflect light off of a mirror and the mirror becomes a light source and you can apply the inverse square law to it. I'm pretty sure a flourescent tube is made up of a bunch of points.

Point is...lowering your lights can make a dramatic difference.

[caferacermike]

So in the end I got it right the first time by running my lights 6" above the water?

[apedroza]

I feel like I'm back in physics class!!!!!!

[RayAllen]

huh, lol.....