[Wet Thumb Forum]-MH - How far above the water surface?

[imported_Davo]

I have been looking at 2 x 150w metal halide fittings for my 4x2x2 tank. Can someone tell me how high they should be above the water surface? Will this be too high a wattage for this tank?

Dave.

[imported_Davo]

I have been looking at 2 x 150w metal halide fittings for my 4x2x2 tank. Can someone tell me how high they should be above the water surface? Will this be too high a wattage for this tank?

Dave.

[EDGE]

(48x24x24)/261 = 105 gallon

150x2 = 300 watt. approx 3 wpg. It is perfect for growing plants especially when MH can penetrate the water quite well. I had mine hanging above the glass lid 5-6 inch high. it is a good way to reduce the chance of raising water temp. However, a lot of light is lost to the room on the way down. I am sure you can keep it as close as 2 inch from the glasslid. it will still give it enough room for ventilation. You will notice the water heating up a little though.


talking about MH lately have given me the motivation to use the MH again

72 Gal, 3 WPG PC 10 hour, pressurize co2 /w controller 1 bps, Fluval 404, ph 6.8
A Canadian's Plant Traders website

[ddaquaria]

i have hanging MH pendants which are about 10" off the middle brace. I built a canopy supported by teh wall in order for the light not to be lost to the room. 2 out of 3 of my 120s have either 425W or 500W, and I'm looking for another 175W pendant to get the 3 tank up to par.

My aquariums are open top. I do not use the glass lids since it seemed to just reflect the light and generate more heat within the tank.

120 Oceanic: S. American Creek/425W-MHs/2228+2026 Eheims/Dupla Reactor 400
120 Oceanic: algae and java fern
120 Oceanic: SE Asian ditch/500 W-MHs/2028+2226 Eheims/Dupla Reactor 400

[JamesHoftiezer]

6-10" is best. They will penetrate 24" just fine at this height. Biggest question is glass tops/glass lenses on the lights to protect from splashes. Any splash against the bulb will make it explode like a cheap firecracker.

James Hoftiezer
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