Lighting for a 90g

Not all dimmers can dim.  You need a dimmable driver but the dimming wires have to be hooked up to something no matter what or the LEDs will not turn on.  I hooked mine up to just a AA battery while I was testing and building them to make sure they would turn on.  So if you don't go with a controller of some sort you will need to hook the dimming wires up to something such as that little 3.50 dimming dial or you will have no light at all.  Can easily be rewired to a controller at any time and they can just be turned on and off with a timer plus you would be able to gradually up the power with the dimming dial as the tank creatures get used to the new light.

 

Kylie before you start your DIY led project i just came across this on reefbuilders. If you are going to MACNA which I am sure you are be sure to check these out.

http://reefbuilders.com/2011/09/06/reefkoi-evoled-reef-led/

 

he donated one to the raffle also so you could try your luck with that

 

Kylie,
You could do 3 dimmers still and put 6 white and 6 blue on the third, but you just have to make sure you have the dimmer set to 750mA like you would the other blue one and you will be fine.  You can mix the blues and whites as long as you power for and pretend the whole string are blues.  That is why most 36 kits come with three dimmers the last string is 6 blues and 6 whites but again you just have to pretend they are all blues and don't power them like whites because they will blow out the blues.  Also heard when doing this it is best to put the 6 blues first in the chain followed by the 6 whites.  Some people set the blues and whites to the same power (750mA) anyway but I think this gives the tank a more purple look so that is why I boost my whites a bit.  The driver has no clue it has white or blue leds tied to it, it provides the same level and type of power no matter what.  A lot of drivers put out around 1400 mA which would hurt the blue leds over time if not instantly.  The white cree xp- leds will take 1300 spec wise, but I personally would never risk that.  On my LEDs I have my whites set to just under 900 and my blues to 750.  It gives my tank a little bit less of the blue feeling but still makes the colors pop.  You can always adjust the power on your drivers white leds to adjust the color you like long as you stay within spec.  The blues most people pretty much put it at 750 and let it go.  The corals need as much of that blue as they can get.
Hope that helps some.

 

You use a multimeter to measure the current on the driver. This part can be scarey for first timers or people who haven't done much with electricity before.  There is a small degree of danger here but as long as your safe nothing to worry about.  I remember my first led setup, there was a pretty high pucker factor at this point /DesktopModules/ActiveForums/themes/_default/emoticons/smile.gif You pulg the driver in with the power wires that would go to the leds to the multimeter instead. There is a little phillips plastic screw head under the driver cover you turn and watch the mulimeter till it reads what you want it to then close the driver back up and your ready to hook up to LEDs.  Never hook the driver up to the LEDs without first adjusting this screw.  They are usually set to the max so you can hurt leds quick if you don't adjust the power first.  Again when/if it comes time for this I can help, but rapidleds instructions are pretty good.  There are a few places that a little more info would have been useful but they are over all pretty good.
You would probably need a dimmer switch for each driver, however you could call/email rapid led and see what they say for sure on that one.
J

 

You'll probably have to adjust the power on all three dimmers if you do it that way because they are set at max from the factory which might even hurt your whites so there is three chances to practice.  Also I maybe building some LED lights here sooner then expected after the good tank news I got yesterday so if I do, I'll call you and you can see some of it first hand before you get yours depending on how soon you start yours that is.  Also I'll be making a build thread for the whole project cuz I know a lot of people here like the build threads, I certainly do /DesktopModules/ActiveForums/themes/_default/emoticons/smile.gif


Your dimmer switch can only adjust power from 0-100% of the supplied current so you don't have to worry about going over the 750mA with the dimmer because it only controlls the power set by the driver.  So if the driver is set to 750mA the dimmers 100% is 750mA.  If the driver is set to 850mA then the dimmers 100% is 850mA.  Hope that makes sense.


J


 

 

I would consider doing 2 12x12

 

I think the 18 x 8 would be just fine for the 65 gallon.  I usually use 16x6s when I do clusters of 24 so the 18X8 makes good sense.  For the 90 gallon i would recommend two panels of 24 LEDs not just one big heat sink just fyi for future planning.  You could still use the 18x8 one on the 90 just would look a little less LED populated as well but if you have a cover over them, no one will see anyway /DesktopModules/ActiveForums/themes/_default/emoticons/smile.gif

 

Kylie, I have a 9x9 heatsink pair with 24 cree xps on it and right now I have it covering my 19" tank and my 5 gallon beside it just fine.  Everything is doing great, even my acropora and montipora, my maxi nems in the 5 gallon even produced a baby so I know they are happy and they are in the outer edges in the 5 gallon.  Total width with 5 gallon, 36", 9" fixture with 60 degree optics 13 inches from the water line very slightly tilted towards the nems.  I'm running my XPGs at about 80% because they were just too bright for my zoas and my duncan on the sand so don't be afraid to experiment with brightness if something seems to stay closed all the time or doesn't open well.