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Old 01/26/2018, 09:27 PM   #21
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Join Date: Jan 2009
Location: Lockport, NY
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Originally Posted by blackway1688 View Post
As I know, every optical level sensor uses Infrared lighting including AUTOAQUA, Tunze...

For Led lighting, it is no problem unless there is infrared led inside it. For T5,T8 lighting, it's a full spectrum lighting and there is a few portion of infrared, so this could influence the detection. I think the lighting should be very close to the sensor to provide the enough power to sensor.
Point 1 - I stand corrected, as it appears that all commonly employed OLSs do use LEDs primarily emitting IR wavelengths to trigger the sensor within the unit upon submersion of the prism.

Point 2 - It appears that not only do some manufacturers of these ATO units caution against LED and other lighting sources overhead in concert with their sensors, but that even light reflection from within surfaces within/ around the structure housing the sensor (i.e. aquarium or sump) can interfere with the sensor. Again, this is not my actual experience leading to a warning, but what is coming from the manufacturers (ex: AutoAqua specifically notes this in their instructions).

Also, since these sensors would be near the top of an aquarium (if not used in a sump), and that is where the lighting for that aquarium typically is, I believe that this may be a fair warning, especially as some aquarists have noted issues when using them directly in the aquarium in some instances. Light intensity, angle of incidence, and spectrum varies, and this is why some may find issues, and others not. I still find it prudent to at least be aware of the potential issue, especially if one encounters problems, as repositioning of the sensor may yield relief.

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