I have decided to do away with my stock canopy and upgrade my lighting on my planted tanks and i will be getting glass lids made. My lighting will be a 2x54w t5ho. I need lids in winter because its so dry here that i am having to top up my tank every couple days as i am losing water at a rate of about a gallon a day.
The lid will be made of 2 pieces and will not be hinged so the 2 will basically butt up against each other supported on the ends. My question is what glass thickness would be suitable for a length spanning 47 inches x 6 inches wide the other will be. 47 x 9.25 inches. Should i go with 5mm glass and will that affect the light getting through the glass? Would 4mm be sufficient and not sag in the middle?
What do you think?