polycarbonate vs glass transmittance

[achansek]

https://www.homedepot.com/p/Falken-Design-12-in-W-x-24-in-L-x-0-25-in-T-Clear-Twin-Wall-Polycarbonate-Sheet-MW-CL-1-4-1224/316676672

Considering this as the lid for my 17g landen 60P set up. 
Data spec sheet from another seller suggests that ~6mm will result in 80% light transmission. Should I consider a simple glass top instead (acrylic warps badly)?

Also, how do I prevent algae from growing b/w the walls? Just sliding U-channels would help?

https://www.homedepot.com/p/Thermoclear-5-8-in-x-96-in-x-5-8-in-16mm-Polycarbonate-Multi-Wall-U-Channel-PCTWU-16MM/205202538

Edited August 3, 2024 by achansek

[DaJMasta]

You'd get much better transmission with a solid polycarbonate sheet.  It's more expensive, but if your tank is only 17G, you don't need it to be thick because the distance its spanning isn't far - probably 1/8" thick would be plenty.  Glass would also work, and would probably be a little cheaper.

 

I don't know what the algae concerns specifically are - usually the answer is either blocking light to the area you don't want it or cleaning it (or heribvores).

[achansek]

Thank you.