Using glass covers with reef lighting

[raym94]

Will the use of a glass cover over the tank diminish the effectiveness of reef led's in terms of the coral's needs? I am looking to keep a tank in a colder room and will need to keep a cover on it in the winter time to minimize heat loss.

 

[obscurereef]

I doubt it would diminish it since LEDs are very bright. If you're really worried acrylic would probably be another option, but probably not a huge difference.

 

[IslandHopper]

acrylic generally allows about 92% light transmission.

glass is generally slightly less than 90%. (though glass is much more variable than acrylic.)

Both cases assume the glass or acrylic is clean and in good condition.

So acrylic is better (as new) but over time, with repeated cleanings tends to get scuffed up and cloudy (unless you want to take the time to polish it back to "like new" condition.
Glass tends to be more durable when subjected to repeated scrubbing and cleaning.

In any case, the biggest detriment to light transmission will probably be algae and mineral build-up on the surface... but if you have the time (and discipline) to keep it clean, it's effect on light transmission should be negligible.