I have switched my scrubber from 24" T5HO over to LED. Originally, I built the scrubber SM100 style, except I made it taller (10") so that it used three T5HO lights on each side, for a total of roughly 150 Watts. For the new LED setup, I used 10 660nm reds and 4 630nm reds on each side. They are "3 Watt" LEDs, but I'm running them at around 500mA, and their forward voltage is around 2.2V, so the total wattage being used is only around 30 Watts.
[attachment=2:326cfw5t]scrubber_leds.jpg[/attachment:326cfw5t]
As part of the conversion, I cut the scrubber box down from 24" to 20", because a 24" box was awkward to fit in my stand. The heatsinks are 20" by roughly 6", and running 15 Watts each, they don't even get warm to the touch.
[attachment=1:326cfw5t]led_scrub.jpg[/attachment:326cfw5t]
When cutting the box down to 20", I also cut down the size of the screen from 22" to 19". It is 9" high, so the potential growing area is still 171 square inches, double sided, which is capable of much more filtering than I currently need.
The first week's growth is greener and more lush than I ever got with T5HO, and at only 1/5 the wattage. Very nice. I plan to move the heatsink up some so that the light is more centered on the screen, but since I'm not feeding nearly as much as I could be, for right now, limiting growth to the bottom 6" of screen is fine.
[attachment=0:326cfw5t]scrubber_oneweek.jpg[/attachment:326cfw5t]
The total cost of the conversion was something like $220, and was quite easy to do.
Heatsinks $40 each
Drivers Meanwell ELN-30D $30 each
LEDs $20 for 10, shipped to US from China
Wire, epoxy, solder, connectors, etc. $20
I'd highly recommend going LED from the start rather than T5 at this point for anyone planning to build a scrubber. The growth with 660 nm red LEDs seems proven. The initial cost of LEDs is similar to that of a T5HO setup, and there are a number of advantages, including no ongoing bulb costs, lower energy costs, no issues from adding heat, and more flexibility in the size of the screen.
Stats:
Acrylic box "SM100" style scrubber
Screen: 19" x 9", double sided
LEDs: 10 660mn + 4 630 nm on each side, run at 500 mA, roughly 3" from screen.
17 hours on - 7 off
Fed from drains at about 700 gph
125 US gallon mixed reef tank, 10 months old