I have never used a splash shield or glass lids on tanks with C/f lighting, and had them sitting right on top with no mounting legs. Never had a problem. I guess the main thing is make sure the fixture is mounted securely, and avoid splashing. Use a GFCI, and of course dont drop it in the tank (seems obvious, but Ive done it!) I think if I was going to use a shield I would use glass, because acrylic warps.
Last edited by cattleman; 12-21-2005 at 11:11 AM..
Plexi glass will warp. So I would forego that. You could use mounting legs to keep it off the water. as long as there's no splashing, you'll probably be okay.
It highly depends on the situation. I have an Eclipse 6 that was retrofitted with screw in PC bulbs. I'm using this set up as a nano reef and it was fine for a while. I machined a splash guard out of 1/4" acrylic and it worked great.
Then I put an octopus in the tank meaning I had to seal the tank completely. The humidity inside the eclipse hood was so great that the starter switch became filled with water and the fixture now flashes like a strobe light when the switch was turned off. You can also hear this god awful electrical arching noise. Needless to say I just unplug the light at night time now... I don't need any electrical fires.
My advice: just do your best to waterproof the electrical workings and you should be fine. Water on bulbs is not an issue. Water on connectors and wires is where you run into issues of electrical fires.
Lighting Splash Shield 
Linear Mode
