DIY LED - new build

[aiaman]

ok, I have some questions on a DIY LED fixture I'm going to do for my 36g tank.
I have been asking Bobofin (very knowledgeable) for many of the answers so I thought I'd ask for your opinion as well, more info to think about. I should point out that all LED's are 3watt XRE R2 white & royal blue.
anyway
I have a 36g bowfront tank that measures 24" deep by 36" across, thus making a surface area of 432 sq in; the tank is also 18" to the sand bed.
The top is not totally open like your tanks all are as there is integral bracing that is part of the design. I have an open area that came with a removable glass cover where my lights currently sit atop (Sundial T5 VHO), 2 10k & 2 actinic x 24watt.
In the first photo I drew a sketch showing the proposed setup via a top down look.

The 2nd photo shows how I plan on grouping the LED's as I will have 2 dimmable ballasts.

My questions are as follows:
1 - The usual compliment of 18 blue & 6 white is recommended for a 20k look. For my layout of lamps on the heatsink (in my mind) shows that 6 lamps may not be enough to spread out and provide white light on all sides. By me increasing 2 white & reducing 2 blue do you think I would have any issues? I believe that I can control output (see wiring diagram). BTW - these extra 2 whites are shown on the far right & far left of the center row.

2 - The LED's on their own have a spread of 130* and if I purchase lenses than the recommended is 80*. Do you think I could intersperse lens & no lens to provide more coverage since the physical fixture will not cover the entire tank. My thought is that some leds closer to the interior of the build not have a lens and those on the outskirts have the lens. By using a lens I can control the beams and have less light flow thru the sides onto the walls.

maybe I am thinking to hard on this but want to do this right the 1st time.

 

[DoctaQ]

you can run it back to 12 and 12 and just run the blues at a higher current and the whites lower, the leds you are using are also outdated, the newer generation of xp-e royal blue is 500mw vs 300ish mw, and xp-g are up to r5 bin vs the xr-e r2. if you want to save yourself some money you can run the whites on a non dimmable lpc and the blues on a eln 60 48d and dim the blue to taste

80 degree optics bareley do anything to the light output, id say dont bother, especially with the xp series since there are no optics wider than 60 deg atm

 

[aiaman]

ok, so I can get XPG R5 white, but blue only XPE royal blue, does that change anything seeing that I will have qty more blue and a smaller tank?
should I still get 18 blue/6 white, I don't want a white tank, more blue color

 

[Cheetos]

12 of each color will give you a 14K look if you are running them at the same current. If you go with dimmable drivers you can set the look to whatever you want. 18 blue to 6 white is going to be really blue not even close to 20K! I've built 28 LED fixtures to date and almost everyone has been 1 to 1 blue to white. If you don't want to go with dimmable drivers then a few more blues then white will be sufficient for the look you want.

 

[aiaman]

so I ordered my kit today from reefledlights and happy so far with the help from the site
I ordered:
1-20"x5.89" Heatsink, 16-CREE XR-E Royal Blue Bin D3, 8-Cree XR-E Cool White, 24-CREE-80 Degree optics
2-ELN-60-48 Manually Dimmable 48V 1.3A, 2 -Plugs, Thermal Adhesive, 2-Cool Tron Fans, 1-12 Vdc Power Supply
hope to get on Thursday and start build by weekend
Will post photos and my results

 

[Cheetos]

Good luck with your build! I hope you like blue!

 

[Bobbofin]

Good luck man!

 

[aiaman]

the good thing is that w/dimmable ballasts you control the blue or white balance.
My strings need to have the flexibility due to my rockwork and with some testing with my powerbrights I believe this will be a very good fixture.
I don't have a 100+ gallon tank so I can moderate lighting at a low price & can control the illumination.
Using a T5 VHO I am not that happy with the results so anything would be better.
Its all about upgrading, maybe I'll move on but for now it looks like it'll be better than the heatsink of a MH

 

[Bobbofin]

I have actually changed my fixture since the demo at the meeting. I changed out six whites for blues, it was too white. I now have 24 blue and 12 white. It has a nice 16-17k look, not as white as 14k but not as blue as 20k. All drivers cranked up to 700ma. As far as XR-E being out dated, they will fit your needs fine. The XR-E bin Q5 cool whites that Reef LED Lights sells put out 107 lumens at 700ma. Sure, XP-E might put out 10-15% more but they don't make optics for them and they cost more. This is like the argument of whether to buy a 3.0 or 3.3ghz CPU for your computer, 95% of the people won't know the differance. The brightness of your fixture will be perfect. If putting right on top of the glass, close to the water, I would not use optics in your 18" shallow tank. You don't need optics to concentrate the light for depth penetration. The LEDs come with 130° optics built in already, that will give you good spread. Need anything else, give me a yell. Too bad you're not close I'd come over and help you. I get more fun out of the process of building stuff than the actually finish product although I enjoy the finished product.

 

[aiaman]

Just received my heatsink
Just waiting now for an enclosure I bought to 'house' my drivers from RadioShack
I got a few rubber feet as well

I got itchy fingers now...

 

[aiaman]

ok, so I had some time to devote to finish the project
it took much time to wire, fit & finish, test and test again
I decided to place the 2 dimmers remotely on timers so that the tank top would not have to bear the extra weight, looks cleaner as well.
I used 2 pieces of 9" strapping to secure the fans to the heat sink w/self taping screws also.
The look from before is literally night and day
With all led’s on (24) the tank has a bit more red than blue hue but still white
with the dawn/dusk led’s on it is totally actinic and reminds me of my hey-day of the 70's w/Jimmy Hendrix & glow in the dark posters (god those were great years)
anyway - my corals pop now and the overall appearance is not the stark white I had before, that was good but this is even better
the greens turn fluorescent yellow, the blues are bright green, just an awesome sight (my wife found me staring and not paying attention to her conversation), so it must have been good
I wish my camera could show you what I see, it was truly worth the box of bandages from the soldering iron and too many rum/cokes

thanks to everyone who helped me along this path

 

[DoctaQ]

aiaman..great build..and if you ever figure out how to take a pic of your tank under blue leds let me know ..those frogspawn look awesome though

bobbofin..the xp-g is much more powerful than the xr-e, and the difference is even more pronounced as you get into higher drive currents..at the 750ma that many of us run, the xp-g puts out almost 55% more light, the xp-e is actually just a repackaged xr-e, although there is a newer hew version that bridges the gap as well as high cri versions. that being said the xr-e is generally still plenty powerful for our needs and my tank still has the xr-e