My tank is 48"x18" and 30" deep
the depth gives me big lighting problems
I want to build a LED set up from what I read 1w per gallon is plenty but does that hold true on such a tall tank when I want carpeting plants
My thought was to make a set up with about 35 white leds and maybe 5-10 blue mostly for night far spread inside my hood using 3w leds
That sounds about right to me. You need to plan on using 60 degree optics and running the LEDs at a minimum of 700mA, but definitely get a dimmable driver so you can dial them up or down depending on your needs, as you observe over time.
I would suggest you use neutral white Cree XPG's with 60 degree optics. You'll want the LED's to be about 6-8" from the water surface. I can hit around 80-100 micromols at 23" with Crees, at 1,000mA, and 60 degree optics (12 LEDs over a 9X15 footprint-- maybe even bigger, but my tank is only 9" wide).
I would use 20-26 LEDs per side, so 40-50 total.
10 royal blues, on their own separate dimmable driver, will give you A LOT of color temp adjustment. Dial the tank however crisp blue you want. DO NOT put optics on the blues--- leave the blues without optics, you need the few of them you'll have to spread as far as possible.
I think I would need 2 drivers.
This depends solely on the drivers you select. I am partial to the Meanwell ELN60-48D which will run 14 Cree XPG at 1,000mA, which you need. It's also dimmable but it requires a little work to make the dimmer function (it's not too bad).
You'd need 4 Meanwells. Three for white, one for blues.
With a far spread in a hood I think I can go without a heat sink. I am not sure if I need a fan
No, you can't get away without a heat sink. LEDs that aren't attached to some beefy aluminum or copper will die, very quickly.
You don't have to use the most costly ones out there, but since you have such a deep tank, you really want to drive them at higher currents, and this means higher heat.
I recommend you look into either some 1/4" thick aluminum C-channel (similar to what Hoppy used on his LED build, which is awesome) or buy two 20X10 heatsinks from www.heatsinkusa.com
, one for each side of the tank. Kind of like an "LED pendant".
I found leds that claim 3w 130 lms bright white with out manufactures name not sure if these are the best to go with
I am also unsure of how to build mounting for leds if I should use tubing grid or L metal stripes to build grid
if I should hang it from hood or put it on legs inside the hood-might be better as it may be safer for times I remove hood but this would be just preference
any help would be appreciated or just ideas about what worked for you on any builds thanks dustiin
If you use 1/4" thick C-channel, you can mount them together using any cheap metal product. You can connect them on the ends and middle using some steel flat bar from Lowes for very cheap. Self-tapping screws and a high speed drill will attach them VERY quickly
If you use the beefy heatsinks from heatsinkusa.com, rapidled.com, or ledgroupbuy.com, then you can just drill a hole in them, and suspend them from the top of the canopy with steel cable. That way, you push the fixture out of the way while you're messing around in the tank.
I prefer using a custom made wood canopy for LEDs, but I'm biased since I'm a cabinet maker and can build whatever I want