IR lighting spectrum harmful to coral and fish?

[halmus]

I'm working on an electronics project that will interact with an aquarium. It's a 2-D axis system that will mount above the tank, below the lights. More details about why exactly I'm doing that will be released later. It's a surprise.

Part of the system is intended to have an "accident avoidance" component to it. Meaning, as this device is moving in the aquarium, I don't want it to bump into stationary objects like rock or coral. There are multiple sensors out there for detecting movement or proximity of an object. Most of those are designed for use out of water, but that's another hurdle. Also, many of the sensors we've been looking at use an LED that emits light (usually in the IR or UV spectrum) and a detector that detects the returning light which you process and make a decision with through some microprocessor or circuit.

That's where the problem comes in. I know UV is used in filtration, however I don't know what intensity or what specific wavelength those UV lights operate at, or what threshold is acceptable, if any in this case. It will be easy to find out what wavelength the UV sterilizers use, and the spec sheets should list the LED sensor wavelength. Would a small UV LED really cause problems? I need to research that more to find out what specific wavelength these UV sensors operate at. I want to err on the side of conservative and not use a UV sensor at all, but I haven't entirely ruled it out.

The real question I have is, "Is IR light harmful to coral and/or fish?" Have you come across any research covering this? I'm going to look more into it and try to find something in Advanced A or something like that. I'll post up anything I come up with in case anyone out there cares. I'd appreciate any insight anyone has though.

 

[-=dieseldave=-]

IR will not hurt any fish or corals. Heaters emit IR so does your remote control for your tv and anything else that gets relatively warm. It's the other end that is harmful the uv side.

 

[halmus]

Thanks for the feedback. I do remember hearing that heaters emit IR now that you mention it.

I guess I was a little concerned because I had read about some people's concern over the perceived lack of research about excess lighting on the end of the spectrum +600 (red) and longer wavelengths (lower freq) beyond that such as IR. Specifically, that some of the "white" LED's might have too much of the red spectrum incorporated. I've also heard that ~600nm LED's can have a detrimental impact on coral health beyond just possibility that they can promote diatom and GHA growth. Moderation seems to be the key because I've seen many stunning tanks running lights like Radions that do have a few Red LED's built in. Those tanks did run all of the LED's built in for at least a fraction of the day. I know that light on that end of the spectrum is the first to get filtered out in ocean water in nature, and that the light on the other end of the spectrum (blues) are what reach deeper, so it does seem intuitive that corals would rely less on the "red" end. That is, depending on their naturally occurring depth in nature.

The project I'm working on would use the sensors almost continually throughout the day, while the lights are on. While not being actively used, I could design it so that the LEDs in the sensors are inactive to minimize any impact they could have over the life of its use.

Anyway, I appreciate the input.