tank cover material?

Hi, first off im not sure if this should be here or in DIY but her goes:-/. I just got my new light fixture for my tank and I want to make a cover to go over the tank. Not a full hood or anything but something like an acrylic or plexiglass sheet to cover most of the top to hopefully stop some evaporation but mostly so that i can get a firefish and prevent it from jumping. My question is what material is good that will not stop the light from penetrating the tank. Its a t5 fixture. thanks

 

I have a 20 long with a fire fish in it and I used a glass top I had made at my local glass shop. I had them cut it an grind the edges smooth. I also had them leave a 2" in the center to allow for gas exchange. I figure with that and my HOB fuge it should be plenty and has worked so far.

 

well i was thinking about leaving just a little area in the back of the tank for gas exchange plus my skimmer so I was thinking that will be good gas exchange as well.

 

I was thinking that after I went through the trouble of building this fish a nice home, if he didn't like it, he could just leave. I didn't think that we were supposed to have a cover on the tank. I tried it before and it always got covered with gunk.

How do you keep the salt creep off the glass?

 

well I wouldnt have a problem with not having a cover on top but i really want a firefish and they are natorious for jumping. i was going to put just some mesh on top instead but my dad, who has had fish tanks for years before this said that a top would also cut down on evaporation. BUT I have read things here that say that tops dont stop evaporation so im not sure.

 

salt creep = take top off once a week rinse with tap dry and replace, simple as that.

Cover = less evaporation - 16 gallon is open top, looses about 1.5 gallons a week. 20 gallon partially closed, looses about 1/2 gallon if that. What they do stop is gas exchange thats why I left gap and have fuge.