MH 175 and enclosed canopy
Bob, I have not asked anything of you as yet.
Now, I may be getting into trouble.
I have built a killer lower canopy for my 125 all glass (about 16 in. high), with large doors that keep *all* light from escaping and easy access to the reef. This thing will also slide forward, so that I can service the overflows, etc.
<Sounds very nice>
The canopy is in two parts and of abs plastic. The top ( or lighting part) is a work in progress.
I have a limit switch to cut off the 175 MH lights at 160 degrees that I can place at the hottest (or any) part of the upper canopy and a 130 make/ 90 break snap disc control for the two 4 in. RS, 115v fans. 
<Have your later input re the lower limit (110) for the high shut off>
Lighting will be, two 175 MH, four 4 ft (40 watt) and two, 3 ft. tubes. By the way, those (White-Rodgers) snap disc controls are great and available from Grangers <Grainger> for only 7 to 8 bucks each and I have tested them for several hours, but not on the canopy !. The limit switch will take care of up to 10 amps and I chose the (3L02-161) with a manual restart instead of an auto restart. I figure that if it cuts the hot lights off, there is a good reason and the problem needs to be corrected prior to switching back on.
<Yes>
My thinking on this project is to keep it light weight so that I can remove it without help and I hope to be able to use a lightweight acrylic shield between the two canopies as I wish to avoid heating up my tank.
This same thinking is the reason, I do not wish any motor in my sump or in the tank.
I am running two Quiet ones and driving the skimmer and the 5 nozzle water movers that are in the lower part of the tank and behind and between the live rock off of one pump. The upper supply (six directional nozzles) are on the other pump.
The two fans are both blowing in and can be partially directed at the acrylic sheet, below the MH lights
<An acrylic sheet below the lights? I would not use one here... and want to mention/ask that you have heat and light deflectors as part of the fixturing above, separating the MH lamps from the ABS sheet plastic making up the canopy?>
This should not cause much pressure, because I will have some holes in the top, covered by a four foot by one foot, black plastic roof heat dissipater from Home Depot, on top of the light canopy.
<On top... but also something inside... deflecting the heat from the structural hood>
My question (before I get further with the upper part of the canopy), is...
How close to those 175 watt, 10k MH lights, can I place the acrylic lens?
<Were these supplied as part of the fixture? As UV filters? To protect against touching, splashing? If so they should be mounted per the fixture. If not provided as a component, I would mount the lamps at least a foot from the waters surface, sans any in-between material>
Do you know at what point the would start to deform, melt or bend etc.?
<Depends on some properties of the specific make-up, thickness... likely not too far from just being near the lamps... in the mid to upper 100 degrees F. Do take care here, contact the dealer you bought these units from. Am cc'ing Dave Adkins here. Dave? Bob Fenner>
Thanks,
Dave Moose

Electrical safety in aquaria
Thank you very much for your input, Anthony.  Trust me when I say it's valued greatly.  I think I'll keep a close on it (for condensation and salt), and buy my own cheaply made plastic cover if necessary, or better yet, a high quality one.
<agreed, my friend>
One more follow-up question if you don't mind.  What, in your opinion is the worst that can happen if condensation or salt builds up.  I know that an electrical arc will be created eventually, but am I just in danger of blowing a bulb, or is there a possible fire hazard here? Thanks again, and a happy New Year to you! Eric Newman
<there are bigger issues here than product application and durability. Regardless of how safe or unsafe any such devices are... every aquarium should have the aquariums electrical life support equipment plugged into two separate lines (for safety in case of non- whole-house outages (single devices fails or breaker trips otherwise). You don't want all of your eggs in one basket, so to speak. The two biggest draws for any system are pumps vs. lights. Those two system are your separate lines. Those lines should be shock protected with ground fault interrupters (GFI). Nowadays, you can even buy an extension cord with a GFI built right into it! If you run your aquarium equipment off these two GFI protected lines, you will have little or nothing to worry about with any reasonable electrical application. Best regards! Anthony>

- IceCap Wiring Information -
Hello,  I was just wandering if you had a direct route to info about IceCap Industries Model 660 Electronic Ballast. Like, where the wires go and what colors... Thanks for the help!
<For all information IceCap, please go here: http://www.icecapinc.com 
Cheers, J -- >