I have the aquaticlife 4x18 fixture over my 10 gal nano. I have to be honest, if I was to do it again, I would get the longer fixture. Get the 24 inch one. The only companies that make 18 inch bulbs are aquaticlife and current. I am unhappy with both of their bulbs. Moving up to a 24 inch light will broaden your selection of bulbs substantially. I have ati bulbs over my larger aquarium and am so much happier with the light than what I get out of the stock aquatic life bulbs on my nano.
FYI, I don't believe the aquaticlife has a dimmable ballast.
FYI, I don't believe the aquaticlife has a dimmable ballast.