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View Full Version : Building a Canopy - Should I put plexiglass under the metal halides?

ReefGirlSara
12/23/2007, 11:07 AM
I have a small current type fixture that is a black box with 1 250Watt MH and 2 PC's, and it has plexiglass on the bottom, enclosing the whole thing. There's a fan on each end blowing the heat through the fixture, and it doesn't seem to cause too much evaporation this way.

I am building a 48" canopy for my new 90 gallon AGA, and I got some good feedback for design ideas, but I can't seem to find any info on enclosing the canopy - specifically with plexiglass on the bottom.

I'd like to know if anyone has done this and if they were glad they did or not. If you did and you are glad you did, how many inches between the MH's and the plexiglass? How many inches from plexiglass to water surface? Do you have a hard time getting your hand in there - or did you make the whole top hinged or how did you set it up for easy access?

I am planning to build this this week, and I am planning on either 2 or 3 250 watt MH's and 2 T5's for actinic supplementation (if they ever show up- ordered from a guy on RC like 3 weeks ago :( )

Thank you!!!
ReefGirlSara
12/23/2007, 11:09 AM
I guess I left out the part saying I'm thinking about copying the current fixture's design idea, and I will be putting two fans on each end to blow air in and out of the canopy. I want to reduce heat and evaporation as much as possible.
cashman95
12/23/2007, 12:57 PM
I would not put the plexi, it will get dirty an hinder your light output. Thats just me though. Put enough fans in your canopy to cool it down and you should be fine. Most pendants use a glass sheild in order to decrease UV rays from HQI bulbs. Its totally up to you....If your plan is to cut down on the evaporation, then maybe, but I wouldnt. Just My OPINION!
OceansWonders
12/23/2007, 04:23 PM
IF your going to that I would not use plexi around metal halides. I would use glass.... IMO you would be better off just having enough air movement in the hood and forget the extra shield much of the heat will radiate through it anyway.
OceansWonders
12/23/2007, 04:23 PM
IF your going to that I would not use plexi around metal halides. I would use glass.... IMO you would be better off just having enough air movement in the hood and forget the extra shield much of the heat will radiate through it anyway.