Oldmac, ive been searching too for the Reflex tubes in the US and it seems Phillips dont sell them there. But there are other brands which does them, as Hagen, the same of the tubes you are using. They sell an actinic tube for marine acuariums with a 160º window. Ive seen it on acuaria webs for around 20$.

Unfortunatelly it seems that Reflex tubes are hard to find in the US.

Im sad to know what happened you and your greenhouse. I gave up growing outdoors after being robbed two years straight. All the worst karma for those sons of a bitch

Be aware, its very probably they will try to do it again next year.

Coming back to LEDs, i think is still too soon to replace large HPS bulbs. probably on about 2-3 years its going to be doable, but currently the extra cost is difficult to recover by electric savings. Spectral tunning, micro grows and suplementary lighting for lower areas seems the areas where currently LEDs may be halpul and cost effective.

Veggi, take care. All the best.

I dont see any advantage on using full spectrum bulbs. MJ likes a lot of red light, at least 60% of total. Full spectrum bulbs emits too much green, IMHO.

Redline, i was trying to calculate the thermal resistance of your heatsinks. 15w on each seems correct, although maybe some less ( about 10) would work better, specially if you are going to run your LEDs at 700mA. Are they about 10*10cm and 2 cm thick (4*4", 1")?

I try too to avoid as much as possible the use of fans. Given the large surface area we have avalaible on a grow room, i think using passive cooling is easier and more efficient, as far as heat dissipating surface is well calculated.

I have a spectrografic chart of a red Cree XL lamp running at 700mA. Peak wavelenght is at 642-643nm. Half intensity at 630 and 651nm. Not ideal, but good enough. Emiting spectrum of red leds shifts noticiably with the increasing temperature. Datasheets spectrums must be taken as orientative. Spectrum emited on operating conditions is always longer.

Although not designed for hand soldering, its possible to do it with Cree Xlamps. Ive done it several times without problems. Some leds have been soldered and desoldered some times and are still working fine. The problem is you need to do it on the top sides, where there is very little space avalaible. I solder the electric contacts directly on the side of the led, where there is no problem if there is too much tin (no shorts with the metalic ring of the center).

I use to put a piece of Kapton tape below the electric contacts, and solder the side of the led to the wire over the tape. Kapton tape do well up to 300ºC. Ive tried to put the solder tip on the tape directly for more than 10 seconds without damaging it

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knna Reviewed by knna on . Building LED lights from facts, no theories I was going to post this at the Perfect LED Grow Light thread, but as some of what im going to post was posted 2 years ago on the stickied thread about LEDs and people still continue developing lights from wrong ideas, i think a thread about this topic is largelly needed. The main problem is related to efficacy of spectrums. When the firsts LED experiments at Overgrow, we work on the hypothesis that blue and red light are more effective. It was an appealing hypothesis that promises large Rating: 5