I've got clear air lines too, gonna do the same thing and use black duct tape to cover about a foot of the lines before they enter the tank.
I figure that will be enough, as the light wont realisticaly be able to travel down the inside of the tubes for any significant length?
The lid of the tank is also designed where any tubes go in, the edge of lid sits lower than the top of the tank, so the line has to do like a 45 degree bend.
I've also made some cardboard guards for the tops of the baskets that I can asjudt as they grow, or just make new ones: