Led optic changing

[BigJim]

I have a question about this light I purchased. The listing said it has 90 deg optics. I think that is too direct of a beam for my tank. If I removed the optics from the light would it then be 120 deg optics? Or do I need to purchase 120 optic lenses and then install them on the light?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330900426092

 

[Ron Reefman]

Last I was told by EG, the leds are now 90 degree leds, but if you remove the 90 degree lenses, it will help with spreading the light (I did this on a D120 over my 55g QT and it did help, but not enough). If you add 120 degree lenses it will spread the light even more. BTW, lenses are cheap, like $.20 each. If you need more info, I have a good contact here in the US who does warranty work for EG. He may even be able to hook you up with 120 degree lenses. I just asked him to send me 100 of them for my 6 EG fixtures.

 

[loqix]

Last I was told by EG, the leds are now 90 degree leds, but if you remove the 90 degree lenses, it will help with spreading the light (I did this on a D120 over my 55g QT and it did help, but not enough). If you add 120 degree lenses it will spread the light even more. BTW, lenses are cheap, like $.20 each. If you need more info, I have a good contact here in the US who does warranty work for EG. He may even be able to hook you up with 120 degree lenses. I just asked him to send me 100 of them for my 6 EG fixtures.

Seems like you know....

I'm still trying to understand the degrees.

For my standard 55g. What would be the best option? I plan on suspending the lights about 4-6 inches from the surface.

I don't want shading on the sides.

Thanks in advance

 

[Ron Reefman]

Seems like you know....

I'm still trying to understand the degrees.

For my standard 55g. What would be the best option? I plan on suspending the lights about 4-6 inches from the surface.

I don't want shading on the sides.

Thanks in advance

Happy to try and help, but I kind of need to know which led fixture you are getting and is your 55g a standard 48" x 18" x 24"? I have some experience as that is the size of my QT.

 

[loqix]

great, I have these right now, but i'm placing another order for more, but I want to make sure I get the correct degree on the next batch.

This is how they look now, you cant really tell the shading too much on the pic tho

 

[raynist]

Looks like you need to move them in the middle more. Looks shaded in the middle and like there is light spillage on the ends.

 

[Ron Reefman]

loqix, that helps some, but you still leave me with questions.

First, as raynist said above, your lights are spread to far apart. The tank is 48" long and I'll assume the lights are standard Chinese cases which are 16" long. You have 2 so take 48" less the 32" of light and you are left with 16". Divide that by 3 (for the 3 gaps, 1 at each end and 1 in the middle) and you get 5.33". So hanging them 6" apart would give you 5" of tank beyond the outside of each light. That would work well and look balanced.

You didn't say how high you have them off the water. But if you do as I described above, you can lower them until the light from the fixtures is just covering all of the bottom of the tank at the outside edges. That may even be lower than you want to get to the water, so just go as low as you are comfortable with. As you said, 4"-6" should be fine. You can see in your pics how much light is being thrown outside the ends of your tank and being 'wasted' on the wall.

I assume you have 90 degree optics now and with a 24" deep tank those are appropriate. You might consider swapping the 90's out from any odd colors you have (odd is anything other than blue and white) to 120 degree lenses so they get more spread over the entire tank. You have way more than enough light to cover the tank (with no 'shadowing') with 2 fixtures. You should be able to grow any kind of coral with those lights and even run them at well less than 100% power.

What brand are they? I don't think I've ever seen D120 type fixtures (a standard Chinese case) with timers/controllers built in. Are those just on/off timers or can they do sunrise and sunset dimming as well?

 

[loqix]

right now they are 18" off the surface, in the picture they are 13" off the water, i'd like to drop them to about 7-8" and have no shading. The reason they are so far apart was cuz i had my MH fixture hung there, but its kinda late now to re-do it. There will be some huge holes in my wall... lol

The 55g I have is 20" from top to bottom

If i'm not mistaken, yes they are 90degree, I asked the supplier i've been dealing w/ @ Twilight (jone)

I dont understand when you said.. You might consider swapping the 90's out from any odd colors you have (odd is anything other than blue and white) to 120 degree lenses so they get more spread over the entire tank.

I'm going to order another batch of lights, but i wanted to know to get 60degree or 120?

Whats the difference between all?

60?
90?
120?

lol

 

[raynist]

If you can't redo it then I would angle both fixtures to point towards the middle

 

[Ron Reefman]

Think geometry.

A 60 degree angle is narrow, so the light doesn't spread much from the timw it leaves the led/lens till it hits the bottom of the tank. So it makes a like skinny 'cone' of light. So the light is very 'focused' and therefore stronger and better for deeper tanks.

The 90 degree lens is a bit wider and makes a slightly wider cone and spreads the light out more than the 60 degree lens (cone) does. These are good for 18-26" deep tanks (more or less).

The 120 degree lens will make a very short wide cone of light and spread the light out even more. To the point that if it is held high above the water, or the tank is deep (24" or more) the light 'spills' out of the tank and lights up the floor and walls (that's just wasted light that you would rather have your corals get).

So if all 3 lenses were the same height off the bottom of the tank, and the 60 degree lens makes a 4" circle of light. Then the 90 degree lens will make a 6" circle of light and the 120 degree lens will make a 8" circle of light (numbers aren't exact, just picked to help explain).

Your 90 degree lenses are just fine in your situation of 2 fixtures over a 55g, 4' long tank and lights about 6-12" off the water.

The reason for switching the UV, violet, red and green leds and moonlights if you have any to 120 degree lenses is so those few leds end up with bigger circles of light in the bottom of your tank, rather than small circles where you can see there the edge of the red circle is and where ther isn't any red. You have so few reds and greens, etc, that having them spread their light around better with 120 degree lenses makes for a more even distribution of color spectrum in the tank.

You can keep your wall brackets where they are and either run a small pipe from one to the other and hank the lights from the pipe so you can space them however you like. Or you tie the 2 drop wires together with another wire and pull them towards each other. So the hanging wire is at some slight angle toward the middle of the tank rather than hanging straight down. Think of a lasso or a cable tie looped around both drop wires and the tighten the cable tie until you start to pull the lights toward each other.

No holes to repair and lights better placed above the tank.

Good luck.

 

[cap032]

Simple solution, connect a rod that runs across and connects to the two bracketts you have in your wall. You can then hang your lights on the rod allowing you to slide them in a little.

 

[loqix]

crap, you guys are the best!! THANK GOD, someone FINALLY explained the whole degree thing... phew!

Ok i'm going to figure out a way to adjust the lights to make the spacing better.

So to make sure, the next batch of lights i order should remain 90degree, correct? As long as I space them correctly.

 

[cap032]

crap, you guys are the best!! THANK GOD, someone FINALLY explained the whole degree thing... phew!

Ok i'm going to figure out a way to adjust the lights to make the spacing better.

So to make sure, the next batch of lights i order should remain 90degree, correct? As long as I space them correctly.

It really is a matter of the coverage and PAR you need along with how high you are going to hang the lights. 90 degree is a good all around lens though.