it will be the light, in doresys tank pics i think the lights are on, and in my avatar the lights were off and i used the flash on the camera, but i have been buying it for years for the kids and i havent seen any diffrence to be honest,it will look just the same in your tank, fill a vase or similar try both filled with water and stand in similar lighting to see which you prefer, but there is also a diffrence to the colour of the whole tank with/without plants in,i found without, tank looked very "pinkish" and with it looked great. good luck hope you can make a descision easier than me lol
shelagh xx