Color of Light from the fixtures

I have two 30" T-5 Aqualights on my 37-gallon planted tank. The light output has become noticeably yellow-green over the past couple months. There are two 18 watt bulbs in each fixture; a 6700K plant bulb and a Colormax full-spectrum bulb. Any thoughts or recommendations for improving the color of the light? Is it just a matter of replacing the bulbs. It seems like I replaced them just three or four months ago.

what colour would you like it to be?

I would like the light spectrum to be a balanced white, not favoring any narrow portion of wave length.

For a really bright white colour imo LEDs are your best bet. But if you only want to change the globes then your best bet would be having a look in your local LFS for the correct globe (sorry couldnt help but im no expert lol) Last time i changed globes in my tank light there were several to choose from and they all had different colours and purposes. i ended up getting the best one recommended for plants and it gave of a pink/orange glow. not very attractive at all