How long grass has been planted? If you just plant them just for a few days, the bubbles maybe simply due to the cut...
Better observe for a few days before conclusion. People say 6500K light tube is better due to closer to what plant needs. It's just 13000K is not as effective as 6500K but don't think 13000K will do any harm - just not effective... as u've already bought it, just use it for a few weeks to see -
Observation is your best ground for decision

Other's recommendation is just your reference...