If the splash guard is not too small, you can find micro compact fluorescent bulbs (I got mine at Lowes, but lots of places should have them). Mine are similar
Shop SYLVANIA 2-Pack 60-Watt Equivalent Compact Fluorescent Light Bulb (ENERGY STAR) at Lowes.com
the pair I purchased was 13 watt micro-mini CFL that had a higher kelvin of, I think(?) of around 5,000K.
Look around and try to find something in that Kelvin range. When I get home later, I'll try to find the exact model specs for you. These very compact CFLs fit into my 10 gallon hood, formerly with incandescent tube bulbs, very well and are only rated at 13 watts each. They have worked great for my plants the past three months.
My CFL bulbs cost under $12.