Glass between halides and water

[hookitbig]

So I have decided to use the two 175 watt halides on my tank. However I dont want to remove the glass from the top of the tank to help prevent evaporation. I plan to have the hood powered with fans to help create air movement to remove heat. Will the glass lids cause any problems and if so what problems will they create?
Thanks again for all the help.
John

 

[m0nk]

You'll likely have issues with heat, plus you won't have the gas exchange... this is a critical piece of keeping your pH levels more accurate. I've also read that it affects alk. If you really need something on the top of your tank you can use egg-crate lighting diffuser (you can find this at home depot or lowes). It doesn't affect the look of your lighting nearly as much as glad lids do, plus it's open to the air. There will still be evaporation, but that's not a bad thing.