LED height from tank and other misc questions...

Hello Hello, I have a brand new 75g cornerflo (48x18x21) sitting in my living room waiting for a return pump and lights. I want to keep a mixed reef and began looking at MH lights however I do not want the heat as I plan to run a canopy. So I have found the wonderful world of LED’s… So here are my questions;

1. I see everyone with the DIY setups hang them and several inches off of the tank. Can I mount the fixture directly above the glass top (the marineland hingy kind) or in the top of the canopy just a few inches off the water?

2. If so? Would I need optics and if so what degree?

3. How many do I need and what colors? I like exactlyobp’s wide spectrum build color, it didn’t appear overly blue or overly white… but I really just want good healthy growth...

I believe this is all at the moment. Also I should mention that I plan to use a typhon controller or a diy ardruino based controller to turn on/ramp up/down the leds…

 

I'll try to answer em in order so I don't get myself lost lol.
1. First I would ditch the glass covers. They block gas exchange at the surface which you really don't want. They will get dirty fast and grow algae and be a PITA to keep clean. Also they hold in heat. If you are worried about jumpping fish, you can look into a DIY mesh top, BRS has a nice kit. Ideally you'd want the lights ~12"-18" off the water. Mine are in a canopy and as a result only 5" off the water. The higher you can get them the more light spread and less spotlighting you'll have.

2. For optics on an 18" deep tank, I would look into 60 degree optics. Of course this all deepends on how many LEDS you go with. More LEDs means you could go with tighter optics and get better penetration.

3. How many LEDs depends on which brand you are looking at. If you go CREE then I would think 48 should do you. Bridgelux you may need to go with more. Again this also depends of what you plan to keep in the tank. I'm thinking with 48 CREE you should be able to keep pretty much everything. As for color thats all up to you, depends on how many wavelengths you are wiling to try and how much work you want to put in.

 

Awesome thanks... do you have any pics of your set up inside your canopy? also being so close I wouldn't think I would have to focus the light as much as there wouldn't be as much distance to throw the light...am I thinking wrong?

 

I think that's pretty close to what you're going to need! The issue is getting PAR at depth, i believe! You may be able to go with 80's to reduce the spotlighting and still get good PAR at depth!

Alot of it depends on what you want to grow in the tank and where! And oh yeah, you're budget and if you're going to do it yourself!

There are different BIN's for Cree led's and different types! Here's some links to some basic reading if you're into a DIY!

But basically a 48 led newer Cree system should do ya fine for most corals, if not all!
the nice thing about led's is their dimmable! So ya run you're whites on one det of drivers, and your blues on another! You'd have 4, and you can dim them to get your desired look, or add a controller to do sunrise/sunset/thunderstorms etc! Pretty cool stuff!

And yeah, i'd ditch the glass tops!

look at rapidled's plug and play kits if ya don't want to solder!

 

I just finished my rapidled build on my 75 gal tank. I built mine into a canopy also. because, the glear from the tank is right at couch height... anyways I used the 48 kit from rapid with 80 degree optics set about 8 inches off the water. it seems to spread out fine, I'm definetly happy with it! It's amazing how much cooler these guys run then MH or T5. I'll try to figure out how to post pics. so, you can get an idea of how I did mine.

 

If you have a smart phone, get the tapatalk app! Easy as heck!

 

That sounds like what I was thinking of, do you get good shimmer?

That would be great... do you think it looks to blue with 50/50 split? the pictures I always see are really blue but I can imagine that being from the camera white balance.....

 

That's what's great about led's! Get dimmable drivers and put the blues on one and the whites on another! You can then adjust them to suit your desired look! Add a controller and you can simulate sunrise/sunset/thunderstorms etc!

 

shimmer is good, not as nice as Mh. but, the crispness of the light is great compared to t5.

here's my tank.. crappy cellphone pics. but you can see how i did it.

 

I love it! I am sold... in the canopy they go!! do you run any vents on top or the sides for fans?