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How to create underwater fish tank LEDs?

Ever seen those glass pebbles that are somewhat opaque?

I would like to place these at the bottom of a 15 gallon fish tank and have it lit up from underneath, probably through the use of LEDs.

I am looking for any ideas of creating such a thing that would be safe to place under water, that won't fry the goldfish.

Food for thought, could you also use Black light LEDs or would that possibly kill the good bacteria in the tank.
There could be a possibility to place it under the fish tank (outside the water), though I would have to remove a structural panel. Would creating an LED mat for underneath the fishtank be easier?

Specifications:
-Powered from a wall socket
-light up and through 1.5" - 2" of the glass pebbles for 1' x 2' aquarium bottom.


Picture of How to create underwater fish tank LEDs?
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theledguy3 years ago
In theory, it is possible to light from the bottom of the tank, But I don't know of a way to completely water seal an LED fixture (a clear epoxy on both sides might do it, but you might risk exposing your fish to harmful chemicals). If you have an "open bottom" stand, you could build an LED matrix in a piece of plexiglass and just stick it underneath your tank (Willard 2.0 has a fantastic instructable for building a plexi matrix). If your stand is solid underneath the tank, your only option would be finding a way to raise the tank clearance somehow, or build a thin PCB with surface mount LED's (this would be very difficult and time consuming). As for the blacklight or UV LED's, you could use a few of them, but I would suggest against using them as a main lighting source, as they don't put out much light, and the can kill helpful bacteria in the tank. I'd primarily stick with cool or warm white, and maybe some blue LED's mixed in.
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