yeah ,,i notices that as well the coated side gos up ,,they clear gos down,,.. ,,,,the clear side is where the light shine out from most,,the coated side is so that it wont direct light from on top ,,thats my guess..but there is on thing i could say ,,the reeflux bulb are amazing ..and the actinic URI are just as amazing ,,if marine depot has that company then yes cheeper is the way to go ,,since this is an $$$$$$$$ hobby ,,but worth it
REEF EXOTICs is located in Long island ,he does deliver 6 bulbs and up for free ...
www.reefexotics.com 516-414-0950 thats the # ,,his name is tony ,,very nice guy ,,,he will give you direction if needed