Temp lid options?

[BContos]

What have you done in a pinch for a temporary lid on a rimless tank while you were waiting on your custom lid to be finished?

 

[Uncle99]

Plastic lighting diffuser, comes in 2x4 sheets, cheap.
You can use it later as a frag rack.
Real small fish could get through the holes maybe.

 

[Bruttall]

Polycarbonate greenhouse panels, cost about 6 bucks for 2x3ft, let's 80% of light thru. Amazon.