10k may be a small part of the issue, but i wouldent rush out to get new bulbs, most people with planted tanks used 65 - 68k, but you can use many difrent bulb temps.
I would assume he means 10,000K. A very common bulb spectrum used in planted tanks. Many of us with 2 bulb set ups run one of these in conjunction with a 6500-6700K bulb. IMO this is the best looking combination. The whiter and more blue appearance of the 10,000K helps balance out the yellow color you tend to get from running a 6700K.
Any bulb between 3,500K-18,000K will grow plants just fine, but flourescent bulbs in the 6500K range tend to put out the most light and anything too far from that spectrum starts to look a little weird.
The 10,000K bulb isn't the cause of any problem. I ran a planted tank with nothing but 18,000K bulbs over it at one point, and every plant was able to grow perfectly well under that spectrum. I wouldn't advise this combo though, unless you like everything to have a strange, purple tint to it.