Cree led lighting.....how much is too much?

[chronic]

Hi guys....I'm new to the forum and just have a quick question regarding Cree leds.
I purchased 2 120 watt cree led full spectrum units. The units have 3 watt emitters and there is 40 leds in each for a total of 80 cree hanging 12 inches above the water line. The optics are a mix of 60 90 120. And they are 4 channel dimmable.
So from what I'm reading I have way over done the amount of leds that should be hanging over my 65 mixed reef 36x18x24. Right now I have them peaking at 40/70 white/blue. So my question is that I don't think my endgame should be getting to 100% on the blue channels over the course of 6 months, so what should I realistically be shooting for with this amount of cree's over my 65. I have access to a par meter but I feel they are useless for led as they don't measure pur, only par. I'm really thinking leds put out way too much pur at the same par as an metal halide or t5ho.

[DrBlueThumb]

I read that par is always equal to or higher then pur. not sure if this helps I am new to leds and reading about pur. Seems interesting And I would like to set up a led unit myself one day. Thanks for the post, maybe someone else with experience will chime in?


Here is nano reef lighhting forum, they are good with led info

www.nano-reef.com/forum/25-lighting-forum/

[chronic]

Thank you for the fast reply. But yeah leds are a fun ride with so many unknowns.
But yes par will usually always be more then pur cause par includes all the spectrums like the green and red parts of the spectrum in white light. But that's more for the viewer, not the coral. Where pur is only the spectrum that the coral wants like between 400Nm to 500Nm. And because of the royal blue, blue and uv leds we are hitting high pur.

[DrBlueThumb]

With me I am trying to grow lower light corals such as paly's, aussi/florida rics, shrooms and zoas only. I realized through playing around over the last 12 years that 4 x 24" t5 h.o at 14,000k-20,000k on a 18" deep tank or less gave me best results. I'm going with this on a 35G rectangle aquarium: 2 x attinic plus and 2 x aquablue plus geisemen power chrome.



I am thinking of going led on my 55G, 4 foot rectangle tank. Or should I just stick with what works, and has proven to work? since I am going all soft corals and that leds may be too powerful?

[chronic]

IMO I would stick with what is working for u. But when buying leds it's important to buy dimmable units, so that u can acclimate the corals u have. The nice thing with overpowered dimmable units is it leaves the option for switching to sps dominated tanks in the future.Leds have been the best thing I ever did for some coral and the worst for others. My tri color anenomes and duncans grow at alarming rates but yet I struggle with zoa's.

[DrBlueThumb]

I see, thanks, I'm going to want to start from the ground up with leds and try it out on trial tanks, with corals I can risk to lose. I'm going with t5 h.o from a hydorponics store the single strip x 4 with individual reflectors that plug into each other because they are the only ones that allow me to intall them into my canopy. I have only 10 inches width by 30 inches length to play with and just can not find a 4 x h.o fixture anywhere that fots and goes for less then $600 including bulbs. leds seem to be comparable in pricing or even more, store bought. So I am Going t5 h.o retro fit so I can cut that price in half.