How would you light this tank? LED experts needed!

[Dbroncoboy]

So I have a corner L shaped tank.... Makes it a little harder to create a lighting for it... 24" deep.. the back of each side is 36"... I want to do LEDs but I am not sure how many fixtures I would have to make, or how to space them or anything.....I also don't know what to do with the lighting in regards to the holes in the top of the aquarium... Should I only place lights over the holes? I am just completely lost... I am interested in keeping some corals in time...but money is tight right now so I don't know if I could go over 48 LEDS.... looking at the 3Ws from RapidLED currently...
http://img340.imageshack.us/img340/6821/img0777bi.th.jpg (http://img340.imageshack.us/i/img0777bi.jpg/)

[der_wille_zur_macht]

If I am understanding your measurements correctly, it's roughly a 180g tank with 1728 square inches of surface area? You're gonna need a LOT more than 48 LEDs to keep most corals - like, two or three times that. Assuming, of course, you want an even spread of light covering the whole tank.

Where you place your lights will depend on your livestock and aquascaping plans - I wouldn't see a problem with just putting lights over the holes, which would let the back corner remain a little darker and shadowy - it could be a really cool effect, but of course, only if you're interested in it.

Read through some of the longer LED threads and you'll get an idea of what's working for most people, but keep in mind that lighting is a highly personal choice, so you are best off buying a few different LEDs and experimenting to find the angles/positions/colors/intensities that work for you. If I am understanding your post correctly, the tank will start out as fish only and become a reef tank at some point in the future? The good news there is you can start by building a low-intensity fixture for your fish only implementation, then expand later if you decide to add corals.

FWIW, most DIY builds are done to provide even lighting across the entire aquarium, with a color similar to a typical 15kk MH, or a 10kk MH with actinic supplementation. Assuming you want intensities to keep an average mixed reef tank, this usually means you'll have between 10 - 20 square inches of surface per LED, and around 60/40 split of royal blue XP-E or XR-E and cool white XP-G LEDs from Cree, all in the highest brightness bins available. You don't want to skimp by buying cheap, no name LEDs: the LED model and bin is important to ensure you end up with the most efficient rig possible (otherwise, just do MH or T5). For your tank, assuming my math above regarding the size is correct, this means you'd be around 100 - 150 LEDs total.

[Dbroncoboy]

Sorry for the confusion, so the blue panels on the back are 36 inches each, but on the front its only 18 inches for each side... Doing the math I calculated it between at a little under 90 gallons... bascically its 3 18x18X24 cubes put together... Those are the outside dimensions... measuring the inside it is 3 17x17x22 cubes...

I am having a really hard time explaining it, do you understand what i mean at all?

The surface area is under 972 square inches...

[AngelAddict]

Depends on your live rock arrangement and what you want to keep. I like the island look,therefore I only need my LED pendants over them, not over the whole tank,saves me money.

[der_wille_zur_macht]

Those are the outside dimensions... measuring the inside it is 3 17x17x22 cubes...

I am having a really hard time explaining it, do you understand what i mean at all?

The surface area is under 972 square inches...

Ok, then cut the numbers I proposed in half. 48 would be a little low for a typical mixed reef, but not outrageous, especially if you were happy with a non-standard spread of light.

[jtl2]

Any live rock or coral to start? If not, then looking at your picture a couple of heatsinks would work (in order to get an even light spread) with white LEDs keeping in mind to arrange the spacing so you can add the RBs later at your desired ratio.

If you are going with some live rock and some corals in the beginning do one side with CWs and RBs at your desired ratio (with the live rock and coral predominately on that side) and the other side with whites only (again with the plan to add in the RBs later).

This would keep your initial cost down and let you add LEDs in the future. The great thing about DIY you can adjust and experiment as you go.

John

[der_wille_zur_macht]

Just to comment on John's comments, I would not do JUST white LEDs on a tank unless you'd seen it in person and actually liked it. Assuming you're talking about "best of breed" HP LEDs, even the coolest cool whites are very warm by reef lighting standards.

[jtl2]

Just to comment on John's comments, I would not do JUST white LEDs on a tank unless you'd seen it in person and actually liked it. Assuming you're talking about "best of breed" HP LEDs, even the coolest cool whites are very warm by reef lighting standards.

Wasn't suggesting forever, but as I said with fish only you could get by on a budget. I agree that a mix is better, but I've got mine set up where you can get an idea with whites only (CREE xp-g) and it's not terrible.

John

[jtl2]

Back to the question...what are the dimensions of the two openings in the top?

[Dbroncoboy]

I'll post a drawing on the design later but the left side is 12x12 the right is 12x22

[jtl2]

You could use two heat sinks and set them up pendant style or in a hood, don't know which you have in mind. The threads here and elsewhere have a myriad of designs as DWZM pointed out.

The top looks clear, does it come off for cleaning? If you don't mind regular cleaning of the top and the top is clear, minimal light loss, you could size the heatsinks longer than the opening and take care of the dark corner.

The typical heat sinks come in some standard widths, but I would think the 8.5" wide version since it is only 1.3" tall with fins. There is a 10.5 wide version, but it is almost 3" tall with fins. Easy enough to fit 4 rows of LEDs on an 8.5" wide heat sink. The heat sink length would be determined by your response regarding the top.

I'm running two heat sinks with 24 3W LEDs on each one and the tank is 21" deep, 46 gallon bowfront, and it has plenty of PAR on the sand. I'm keeping SPS, LPS, zoas and a Crocea clam.

Highly recommend dimmable drivers for the LEDs, which will help get the color mix you want whenever you get all the LEDs mounted.

[Dbroncoboy]

The top isn't removable... I don't really know how much the lid would affect the light... it does seem pretty clear.... Perhaps I could put the lights closer to the top of the tank with wider optics to try to light the whole thing... I plan on building a canopy.... I was thinking two clusters of LEDs... Maybe the right optics could get the whole tank lit... I really appreciate all the suggestions...

[der_wille_zur_macht]

Acrylic is pretty efficient for light transmission. The real issue is that the bottom of the acrylic will get coated with salt spray and reduce the light's intensity pretty rapidly, hence access to clean the bottom surface is important.

If you want to put the LEDs close, you definitely need wider optics, or none at all (which will provide the widest distribution.)

[Dbroncoboy]

Thanks... you guys are really helpful... as it stands now I am going to do two banks of 24 LEDs... If anyone has other ideas or suggestions please let me know... Thanks for all the help!