calling all LED experts...

[Ron99]

Originally Posted by ner'T'

Thanks for the input everyone. Good to see some more supplier options too.

I might start out with my Biocube 8, but ultimately I want a fixture for a 20-24" cube setup. My current 20"x20"x24" has a 250w MH.

I didn't realize dimmer would change the K, I thought it would only adjust the intensity of light.

How expensive/complicated is a controller for simulated sun rise/set?

Thanks again

To replace a 250W MH you will want at least 60 degree optics. Assuming your cube is 20" wide by 20" long and 24" deep I would say you would need 5 rows with 8 LEDs per Row. Space the rows 3 inches apart and space the LEDs in each row 2 inches apart.

As for the dimming and tuning colour temperature what you do is run the blues and whites on separate drivers so you can dim the colours independently of each other. I run my blues at 100% and my white at 75% and I really like the colour I have. Somewhere around 16000K I would say. I could get closer to 20000K by dimming the whites further.

Controllers can be as complex or simple as you like. I spent about $130 or so on parts for an Arduino based controller. I am running PWM dimming drivers rather then 0-10V dimming so it is a bit more complicated and I am not a programmer so messing with the Arduino is a bit trial and error for me. But the voltage controlled drivers should be easier to run off a reef controller as suggested. You can do really nice effects. I have my blues slowly coming up to brightness over 30 minutes followed by the whites slowly coming up over the next 30 minutes. Sunset is the reverse at the end of the day.