Safe distance of LED to GLASS for HOG UAS; Will HOG UAS heat the tank water?

[siameez]

I have a 29 gal FW tank, medium load, and want to build a HOG UAS.

I'm figuring on using 4 red 3W LEDs with a CPU heat sink behind each LED

I'm wondering how close to the glass I can safely have the LEDs without worrying about the heat stressing the glass and causing damage. I don't want to have a glass "blow-out" someday...

And will a HOG UAS heat the water in the tank significantly?

This whole Algae Scrubber concept is fascinating and seems like an interesting and relatively simple project to do...

Thanks!

[SantaMonica]

Welcome.

3 watt LED's really don't heat the glass at all, much less the water. Even with our new HOG3x with 9 LEDs, the glass is cold even on a small 10g tank.

For a 0.5 size unit, you will only want one, or at most two, LEDs, because the small growth size (about 3 x 4") will get too much light with four LEDs.