Decided to forge ahead & start using this fixture even though there's still a fair bit of work & experimentation ahead. A major part of the experimentation is of course how my critters react to the lighting change. Burned the midnight oil last night, pulled the old MH/T5HO monstrosity & hung the LEDs. Running them as is, with loose wires all over on only one power supply & 3 dimmers has it's limitations, but I figured the sooner I get started, the sooner I'll see how the livestock fares. The LED configuration with respect to numbers & colours is where I intended for the initial trial, so damn the torpedoes.
I started with the fixture approx. 12 inches above water surface this morning. The 12 volt power supply, set at just under 10 volts is on a single timer & changes in intensity are done manually, either with the 3 dimmers or raising/lowering the fixture. I cut some wooden wedges to mount the outer rails, giving them a 10 degree inward tilt. I'm hoping the increase in focus to center, away from the sides translates into less glass cleaning! I'll probably be moving the outer rails a fraction closer to the center to further tighten light spread & minimize spill over the sides where it's neither needed nor wanted. The Hagen 77 gallon is relatively narrow & my rock scape with corals runs pretty much down the center longitudinally. It will take some tweaking to find the sweet spot of LED spacing in conjunction with height above tank, but I don't think I did too bad with my initial guess in that regard.
The fans are definitely audible & although lower in noise level than those I had cooling the ends of my overdriven T5HOs, some of them have a mildly irritating high pitched whine. This may be due to the fact that they're running below rated voltage or simply because they're cheap, dunno. The more I bump up the voltage on the LEDs, the faster they run & actually quiet down a little. Might try cutting all the fan leads & running them full speed at the rated 12 volts to see how that works out.
I like the look, plenty of shimmer & great colours on the coral. The tank is more accessible since the fixture is mounted higher than the old set up. The fishes certainly noticed something was different this morning and were a bit shy, but in less than an hour they were behaving pretty well as usual. I have a spawning Maroon clownfish pair so it will be interesting if the lighting change has any impact on their schedule. It's been about 4 days since their last clutch hatched and the female should be about ready to put down another.
After a couple of hours, I lowered the fixture by 2 inches to 10 above surface & bumped up the voltage on all 3 colours of LED. That'll be my sophisticated, high tech dawn/dusk program until I get more power supplies & timers. Numbers are now as follows, measured at the input & output of each dimmer:
LED colour, Dimmer input VDC, Dimmer output VDC
10000K & 6000K White, 9.63, 7.98
Royal Blue, 9.73, 5.51
Blue, 9.83, 5.51
Not entirely sure why the difference in input voltage values, since a single power supply is driving all the dimmers & lights. I assume it's due to slight variations in wire lengths feeding the dimmers & probably the different number of LEDs being run by each dimmer. The dimmer running the Blues is driving only 5 LEDs, Royal Blues number 8 for that dimmer & the one working hardest is the dimmer running both the 10000K White & 60000K White which total 14. I'll have to keep an eye on that one since it's probably close if not over it's 8 amp limit. Haven't made any current measurements, but by underdriving the LEDs with the low forward voltages, they won't be drawing anywhere near their maximum of 1 amp, so should be fine.
Inserted my power monitor into the circuit & the fixture with voltages as set now is drawing 140-146 watts. Should equate to some useful energy savings over the long term, although it seems that my heaters will be running a little longer without the Halides doing their thing during the midday lighting period.
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