DIY LED Bulbs?

[lalc]

I might be setting up a 460 gallon tank. will need to light a tank that is 30 wide and 37 tall FISH ONLY-not coral. the tank will be installed in a Bar.
I am doing what I can not to have a 460 gallon heat sink.
I see the DIY 3w Cree ect.

I am looking to light that tank and I was wondering if any one as tried the 10w/20w bulbs I see online?

And just to be out side the box-or show ya'll I have no idea what I am up against.

price is right why not simply install this light with a reflector around it.
http://cgi.ebay.com/ebaymotors/2-pcs...Q5fAccessories

[der_wille_zur_macht]

A few comments:

First, you must understand your own goals and priorities, and you must understand if they are the same or different from those of the people who are building DIY LED rigs. Most people doing DIY rigs are looking for the most efficient method of growing corals possible. Hence, they want the most efficient LEDs possible, and they want to use them in an efficient manner.

That alone rules out "budget" LEDs and the vast majority of bargain pre-assembled LED luminaries. A typical best-of-breed cool white HP LED (as an example) might produce 130+ lumens per watt. A typical bargain basement LED might produce 60 lumens per watt.

So, for most people, that rules out the cheap LEDs and assembled luminaries you see on eBay.

But, let's suppose for a minute that you don't care about efficiency and you want to use cheap pre-assembled luminaries (they're not really "bulbs"). I would still be careful to understand your criteria in order to select the most appropriate luminary you can get your hands on. The one you linked to would be a terrible choice, because it removes another great advantage of LEDs - they are highly directional - meaning, they emit most of their light in a very narrow angle. The fixture you posted kills this advantage, because 4/5ths of the LEDs are pointed sideways - on a fish tank, you want them pointed down! Sure, you could slap a reflector on that, but even the VERY BEST reflectors in the world won't stack up well compared to the inherent directionality of an LED. So, you've got a very low efficiency fixture and you're making it worse by arranging the LEDs such that a reflector is required for their use.

Finally, I would argue that even if you THINK you don't care about efficiency, you SHOULD care about it. People often make the unfortunate conclusion that a fish-only tank requires less light, so the efficiency of the LEDs used is not important. This strikes me as poor reasoning - efficiency is still just as important! It's just on a different scale.

In other words, if you were considering spending $200 on bargain basement LEDs, you'd probably be better off in the long term spending $200 on a smaller number of more-efficient LEDs. If you designed the fixture correctly, you could end up with the same amount of light, but for a lower cost of operation.

[lalc]

OK that answers the save now pay later part.
A point I did not mention is that in addition to being glass the aquarium has 3/4 inch glass so the iron content tends to make the tank look darker then it is.

[MosMike]

Originally Posted by lalc

I might be setting up a 460 gallon tank. will need to light a tank that is 30 wide and 37 tall FISH ONLY-not coral.

So your actual light requirements are very low. Check the topic on linear design. I think that a couple of strings with 2" spacing on the entire length would be enough.

Those 10/20W leds will create uneven light spots.

[lalc]

I ended up using three 60" oddessa T5 fixtures.
Total cost 550.00 including digital timer.
The tank is 18' long 36" tall 24" wide.
http://www.youtube.com/watch?v=-3AqusIWJ4E
906 watts total
2*10k and 2 attinic per fixture.
around 1 dollar per 2 watts I am very pleased.