FEELER: LED group buy

[surfer85]

You can open them up and manually dim them to where you want them. It's not convienent but for the time being I'm going to do it manually. I don't plan on dimming often.

The Drivers are dimmable but you need a dimmer (0-10 volt source) to dim them. I know a few people were working on some modules to do that but I have not heard of anything completed besides using another voltage source to do this.

[drainbamage]

Also an interesting piece of info, LPS don't do very well with LED's. Just something I noticed is most LED builds. People have said that Softies and SPS do well tho. Most LED builds are to strong for LPS. They don't extend much and stay small, but they do multiply quick tho. You should check out info from EvilC66, reading his post's have helped me learn a lot. I read that the Cree XRE's are even over kill for most builds. The benefit of using CREE's newer, more powerful LED's (higher lumen's), is that they can be under driven. This would give decent lumen output and run cooler, which in turn extends the life.

I'm by no means highly knowledgable on LEDs, but I just wanted to throw something out there on the subject of LPS's. It really depends on the LED setup you're doing as to how they'll respond. If you have fewer # of LED's running at a higher wattage, yes, you can actually burn the LPSs. This is especially true if using a tight focus lens. However, a larger grid # of LED's running lower watt and/or wider dispersion lenses will not hold this same statement true. There's such a variety of ways to set-up an LED system it's very difficult to make a blanket statement like this, as opposed to PC's where besides the size/color of the bulb, the characteristics are all very similar.

[scubajay]

I'm by no means highly knowledgable on LEDs, but I just wanted to throw something out there on the subject of LPS's. It really depends on the LED setup you're doing as to how they'll respond. If you have fewer # of LED's running at a higher wattage, yes, you can actually burn the LPSs. This is especially true if using a tight focus lens. However, a larger grid # of LED's running lower watt and/or wider dispersion lenses will not hold this same statement true. There's such a variety of ways to set-up an LED system it's very difficult to make a blanket statement like this, as opposed to PC's where besides the size/color of the bulb, the characteristics are all very similar.

I second this, and would like to add a note:
LEDs are great for producing a very narrow spectrum of light. By doing this they use less energy to produce the light you want without the byproduct of an abundance of undesirable light. This is where your typical florescent/MH lighting wastes a lot of energy by creating frequencies which produce heat in your aquarium, as well as light more readily used by undesirable algae.
However, because of this fact an LED producing "usable" light for coral will look much dimmer than a florescent bulb producing the same amount of "usable" light (because the florescent bulb is making a lot more light that is undesirable, thus looking much brighter to us, but not so much to the coral). As a result people have tried to blast their tanks with LEDs to look as intense as they are used to seeing it with florescent, and as a consequence the corals are bleached. LPS seem to have been the most affected by this, but all corals feel the effects. This has also mainly been the result of people using lenses to further concentrate the light produced by the LEDs and quite literally burning a hole in their corals directly under these lenses.

Moral of the story: LED's have huge advantages, but just like there are differences between how you use T8s, T5s, Power Compacts, Metal Halides, and any other form of lighting, you should try and understand how to implement the lighting so as to best serve you and your corals needs.

HTH everybody.

[mextli]

After more research, I've found that Acclimation is key. Average acclimation should be around a months time for corals to get use to LED's. Even when fully acclimated the LED's shouldn't be ran at 100% (if close to water level). I've read up on some polls of people getting crappy or good coloration. Most of the people with 50/50 blended LED set ups said they have crap coloration on all their corals except for zoa's and a few LPS. There are a few people with similar set ups that have good coloration, and they got it with slow acclimation. Evilc66 stated to start out at 25% and move up 5% each week. As long as the corals react positive to the light increase.
I'm not sure if it's true but I read something interesting. One hypothesis of why LED's give poor coloration compared to MH or T5's, is due to their narrow light spectrum. Since MH and T5's produce a wider light spectrum, the Zooxanthellae in corals compensate to protect against a broader light wavelength. With LED's producing such a narrow light spectrum, the Zooxanthellae is expelled from the corals because it is not needed for protection. Take my post with a grain of salt and I encourage you to do your own research. I just like "Reef Speak" and all the tech behind this hobby. me<-