Could be a coincidence but for now, just leave them out I guess.
The lights I was referring to are for tanks, they have them all different lengths. Might be harder for small tanks.
I have a plant like this http://www.mainevolunteerlakemonitor.../Hornworts.php
and it's growing daily. i've had to trim it twice in 2 weeks already with a standard light that came with my tank (15watts). Not the prettiest, but might be something to look at if your other plants die.