DIY LED Help!!

[LSBBA]

I am wanting to do a LED fixture for my pico build. It is a finnex 4 gallon tank that has the following dimensions 12 1/4 x 7 1/2 x 10 1/4. I am wanting to use orange corals in the tank so I really want them to pop during the daytime and some awesome blue color in the night time to make them pop. I am thinking of acans, plate corals, zoas ,and softies. So my questions are the following:
1. How many LEDS should I use?
2. What different colors?
3. What size heatsink should i use? 6X9 or 4.25
4. If I dont have a controller should I still use a dimnable driver? ( I am thinking of getting one )
5. IS there a way to custom make a pendant led light? (Like the par 38)
6. How far up off the tank should I use the lighting?
7. Should I use a red or green or purple to make the colors pop as well as the whites and blues?

 

[gaberosenfield]

Here is the site of a dallas company that makes custom 9 watt par 38 bulbs. Less wattage than many, but probably enough for a shallow pico:

BoostLED also has some customizability:

But it will probably be cheaper to DIY a small fixture. Dimmability allows you to turn down the light intensity if its too bright. It also allows you to turn it down temporarily to acclimate new corals. Unless you have multiple dimmable channels, like one for blue and one for white. Then you can use dimmability to adjust the color temperature.

 

[matt_longview]

I would not go with a 3w LED fixture. I'd suggest doing a build with 1w LEDs and only running about 7 or 8 watts.

 

[niteowl03]

I would look into running 12-18 watts with a dimmable ballast. Between the ability to raise the fixture and dim the LEDs you should be fine. As far as color it depends a little on what your preferences are as too how much blue you like. But to gain the best spectrum you need a combination of:

royal blue (450-465nm)
blue (465-485nm)
neutral white (3700-5000k)
cool white (5000-8300k)

You could add one of the cree red-orange LEDs to help make your orange colors pop.

You could run a 4.25"x6 heatsink and be fine with 4-6 LEDs. My final recommendation would be 1 cool white, 1 neutral white, 2 royal blue, 1 blue, and 1 red-orange(or royal blue if you dont want that one) with a dimmable meanwell driver.

As far as height off the tank it will really depend on how high you turn up the driver and the space you have available, but with the dimmability you should be fine

 

[LSBBA]

i do like the idea of running the orange and extra blues to make colors pop. would the royal blue be for night use or just the straight blue?

 

[niteowl03]

@LSBBA wrote:

Neither, I would use all those suggested for daytime lighting.

If you wanted to do nightlights then you could grab one of the moonlight kits from RapidLED and I would use 1-2 royal blues.