# HQI Height from water surface



## Skyfish (Jun 8, 2004)

What is the optimal height from the water surface for placing 2x150W HQI fixture? This is going over a 122x50x50CM planted tank. Amano places them at 30cm from the water surface.

I'd appreciate any input.

Cheers!


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## AaronT (Apr 26, 2004)

I was going to say 12 inches so 30 cm sounds about right. Any lower and you'll get heat issues with the water. Any higher and you start to loose light efficiency.


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## Freemann (Mar 19, 2004)

I have kept them at 20 cm and now I keep them at 30 cm, both worked fine, heat issues in the Summer you surely will have. This lambs are like stoves in the summer room heats a lot, I was even considering some kind of hood to convey the heat outside the house in the summer (I have 3 x150w MH above a 150 cm tank).


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## Skyfish (Jun 8, 2004)

Thank you very much Aaron and Freemann, that is the answer I was looking for. Initially I had a hood that was sitting on the tank and the HQIs were about 12cm over the surface, and yes it was an oven in there, but I had a chiller, which over worked sheesh! The pearling was fantastic of course. Finally I decided to make a hood, which is drilled and fixed on the wall behind, but that turned out to be about 42cm high, now I don't get any pearling, BUT the chiller is more efficient now, temp stays at 25c. So I am about to bring it down to about 30cm, that should do the trick.

Thanks again.

Cheers!


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