I'm looking for a sheet of acrylic or plexiglass to protect my LEDs from the water.

Does HD or any place like that carry something I could use?

Home Depot in the back!
they have some thin stuff like 1/8" that will work perfect. its only like $4 for 2'x1'

they will bow and deform pretty bad when placed over the tank.

i would opt for the more expensive polycarbonate (lexan) as the moisture has no effect on it.

why do you want a cover tho? to keep fish out? cut down on evap? i for one is not a fan of covers. they collect dust overtime. scratch too easily, condensation form on the plastic. will get salt spray...all these factors cut down on the amount of light passing through. also it prevents gas exchange too

i would rather use those DIY window screen

My LED fixture sits in the rim of my 10 gallon tank so I will need something to protect the LEDs and wires from salt, water, and corrosion right? or will I be fine going with a windowscreen top?

ahh..if thats the case, cant you just cut a piece the put over the LED fixture instead of the whole tank?

I should have been more specific. That is exactly what I am going to do, get a piece the size of the fixture. The fixture almost takes up the whole top of my tank though.

thats what i thought he was going to do? just protect your leds. i didnt know you wanted to cover your whole tank.

eh..cut me some srack, engrish isnt my fuurst rangulage.