Well call me crazy, but I have completely reversed my use of the LEDs on my fixture. I know; I know . . . I must be loco
Anyways, there I was looking over past TOTM's and I just couldn't stop looking at how saturated and not pastel like the colors were on Radium lit tanks. Then I was taking measurements in my tank. Things were all in the 400 to 500 range. Then I got thinking about the few tanks I've seen that use pure LED that I liked and I came to 2 conclusions. Those tanks had lots of LEDs giving good coverage AND many had the fixtures set much higher than what I would consider normal which I assumes translates into a more even spread of light. I also thought about the fact that when I saw problems in my tank with what I determined to be too much LED light I was in fact running the LEDs for 14 hours straight.
So . . .
Maybe raising the lights to even the spread and running the LEDs for short duration would be ok. Maybe I could even simulate the 1000 PAR intensity of a 400 watt Radium bulb with a combination of T5 and LED.
Here I have a fixture that is working superbly well BUT I felt it could use a little more "punch" BUT I'm terrified of LEDs "burning" my corals
sooo . . .
I raised my lights up so the bulbs are now 21 cm (9 inches) above the water line and came up with a light schedule that uses 4 hours of LED light heavy on the blue side (Radiums are heavy at 450 nms) and that ramps to 100% power BUT only for 1 hour at midday. All together with my very weak all blue sunrise and sunset plus the midday peak. My corals now get a total of 8 hours of LED light, but only about 2 of those hours are above 50% and 4 hours are below 20%.
It's only been 4 days since I started this experiment but so far no ill effects that I can see. In fact during that intense light period my 'nem and my goni throw their arms out as far as they can and I get incredible polyp extension.
Basically I'm trying to emulate the intense 1000 PAR of the 400 watt Radium by raising the fixture high enough that hopefully there is an even distribution of light especially with the T5s filling in on the sides.
We shall see I guess