[Canadian]

The problem with removing the glass cover is that you're going to expose your T5 reflectors to salt spray and humidity which will lead to pitting of the reflectors and eventually diminish light output.

Then the other problem you have is that if you choose to protect the reflectors by putting the acrylic shield on the fixture you're going to trap heat in the fixture around the lamps causing them to burn out faster and lower the PAR produced. Ideal T5 output occurs when the cold spot on the lamp (the end where the label is on the lamp) is kept at a temperature around 115-120 F. And this is not simply accomplished by blasting the lamps with a fan because the air should be directed at the cold spot on the lamp. The concern regarding overheating the lamp when leaving the acrylic shield in place is negated when you have a fixture with active cooling. And again, this is why it is prudent to purchase a quality T5 fixture - you save on lamp replacement costs in the long run and you get better output.

One of the trends I've noticed in this thread is that the majority of posters are relatively new to the hobby. I think what unfortunately happens is that new hobbyists read that T5s are great and see people keeping higher demanding corals with them. So they've done part of the research when it comes to making a lighting decision but they unfortunately miss part of the story - the important part where lower quality fixtures produce significantly less light output and the importance of things like high quality individual reflectors, active cooling over the cold spot, and appropriate lamp shielding among other factors such as quality of ballasts.