DIY Metal Halide/PC Hood

[kzziboy]

Built a canopy for my 55 gal. Want to mount two 175 watt Mh inside on either end. How high off the water should they be and what type of protection do they need. Just a pane of glass? Does it have to filter UV light. I don't want water to hit them and have them explode in the tank...
Thanks in advance!

[OneDummHikk]

It should be UV filter glass if you are using non-protected bulbs (I can never keep up with which are which). About 9" off the water should be a good starting point. Build the canopy so that they start out at about 12" and then you can lower them if you need to.

[ckusnierek]

SE (mougle) bulbs need no UV protection but DE (HQI) do. Make sure if you use DE you have the glass filters in place...

[kzziboy]

They would be the SE or mogul type bulbs. Should I still use some sort of glass top or shield? The bulb will be about 7 or 8 inches above the water, maybe even 9 inches. What are we talking here? If one little drop hits the bulb, will it break? This is obviously my first metal halide setup, I don't want to make a huge mistake.

[ckusnierek]

you do not want glass on top of the tank.
@ 7-9" I would not worry about the bulbs getting splashed.

[kzziboy]

Thanks for the info everybody!!

[kzziboy]

I have the Canopy built and I have since purchased 2 Reef Optix 2 reflector shields with the Mogul base pre-installed. It now turns out that the bulb will be about 6 to maybe 7 inches above the water. Again, since this is the first time I've used Metal Halide Bulbs, I don't want to make a big dangerous mistake.
What happens if my protein skimmer "malfunctions" and sends a large mixture of micro bubbles into the aquarium, they in turn break at the surface and send a fine salt spray upwards... How much can these bulbs withstand when it comes to water? Am I playing with fire here or am I over-reacting?
If I do need some sort of guard, what should I use? I would assume it's something a little more advanced than just an "All-Glass" aquarium hood.

Any help is appreciated!

[OneDummHikk]

You are over reacting. It can be nothing more than 1/8" glass but build you a "water sheild" to keep the water off the bulbs. And no, it doesn't have to be anything more advanced than an All-Glass hood.