Hi,
I am buying a 32g this weekend and it comes with a 2 bulb fixture, the two bulbs it comes with are 20w each, 4100k and a 18000k. Is this ok for growing plants? I'm doing non-co2 and have low light plants so I'm not looking for a setup that produces fast growth, just something that will keep them happy and alive and I don't want the algae to build up too much.

The color temp usually doesn't mean much in terms of plant growth, both of those bulbs will grow plants.

Now whether you like the color is a different matter. The 4100k is a cool white and will have a yellowish tint to it (compared to higher k bulbs). The 18000k has a violet tint to it. If you like the colors, keep them. If you think the 4100k is too yellow try a 6500k or above bulb.