halide question
 

since i started I've been using a 3mm sheet of glass to block out the excess UV from my two hqi's, but now with a 1x400 mogul, I don't really need a sheet of glass any more do I? I've never had heat problems with a sheet of glass, but with a 400 watt would it cause the temperature to skyrocket?

A misconception with 400w is you can have them higher up with more air movement.If you have the space that is

i have lots of space, the whole aluminum housing will be hung from the ceiling so I'll be able to adjust it heightwise, so no glass?

Only HQI bulbs need a piece of glass because they produce UV rays. A mogul based bulb does not produce any UV rays so it does not need any glass. Hope this helps.

Glass over the tank will actually cause greater heat build up. Plus it will stop needed gas exchange. I would never recommed glass over the tank. With HQI It is best to have a glass cover on the light fixture

J

Not so sure about this statement:
" A mogul based bulb does not produce any UV rays so it does not need any glass."
I agree with Jason having tempered glass covering the light is better. Any salt spray is going to accumulate on hot surfaces faster. If you get some on the bulb it may cause some hot spots on the surface of the bulb and burn it out.

ya i'm with you on that one, i'm pretty sure moguls produce the same type and amount of short wave uv radiation, but moguls have an out envelope, to retain the harmful type of uv exposure, correct me if i'm wrong :smile:

ya i'm definitely ditching the glass jason, wouldn't trust it with a 400 watt, however i'm definitely not a fan of the ''non-covered tank'' especially with such aggressive eaters, and my fairy wrasse, whose always so hyper and an active jumper, so what could i use for a cover, eggcrate, too hot for eggcrate maybe? the bulb will be no closer than 10'' from the surface

Mogul base bulbs do produce UV but the glass envelope of the bulb is the shield. A mogul bulb is nothing but a HQI bulb with a built on UV shield.
ALL HQI bulbs MUST use a separate UV shield.

what problems does the UV cause,I know the sun produces UV and I dont hear the ocean complaining