The #1 problem with LEDS are not the LEDs, it is 100% operator error in my opinion.
The main problem is people driving the intensity of the LEDS too high because they dont have enough of the fixtures to cover their tank. $750 radions are just a huge ripoff imo. i would never buy one... you could buy 3 + of the "cheaper" Chinese fixtures for the same amount.
rules for LED SPS tanks:
1. LEDs need to be placed higher
2. More fixtures per tank
3. driving each unit at no more than 40-50%
even with 120 optics, the lights are still very focused, you'll get lots of hot spots and dead spots. by placing them higher and closer together at a lesser intensity, you eliminate all of those problems.
I don't think it's operator error so much as mis-led operators, but I agree with you on pretty much every thing else. When we look at a tank with a "cluster" style LED over it, our eye sees the light spread as much more even than it is. When you look at par graphs for the Radion for example, it looks more like a spotlight than it looks to the eye. If you could see the par in the tank the same way, you would see intense spots under each fixture.
If you want to use that style light, you need to get the more intense area of par to be very close to the next fixture and then the overall spread will be more even.
I am convinced that the eventual LED standard will be a large panel with an even spread of emitters. Pretty much every successful SPS reef I've seen that use LEDs either use:
1) The panel style like the chinese fixtures and stuff the top of the tank with them
2) The LANI or Sicce style fixtures that just cover a large part of the tank area with a blanket of lens-less emitters.
3) The cluster style fixtures but stuff them close together so that they end up acting more like the panels anyway.
I've seen more successful SPS reefs with blue and white led fixtures that conform to the above types than any cluster or full spectrum LEDs.
Notice this month's tank of the month. It uses 13 AI sol Blue fixtures. Blue and white only. Notice in the video that there is little to no shimmer? That is because there are so many sources of light overlapping that they cancel it out. T5s do the same thing. When you have enough LEDs and your spread is even, you will lose a lot of the shimmer - to me that is fine, but a lot of people here list the shimmer as a prime reason for loving LEDs.
Strong shimmer is bad - it means your light source is too concentrated in a few spots.
So if you are doing it correctly, you need a lot of LED emitters. That then begs the question- If you need a ton of emitters and the cost to purchase is astronomical and the electrical use is close to that of traditional lights, what is left to drive you to purchase LED? If that decision was on the table in front of the customer with all facts in hand I think a lot less people would choose LED, at least until prices come down.
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