Excesssive Pearling?

My plants are all growing well with N,P,K and traces fertilization, as well as pressurized C02, but recently there has been a sudden increase in both brown algae and pearling. The Parrot's Feather in particular is covered in bubbles, and to a lesser degree the Wisteria as well. On the later, much of the pearling seems to come from the beginings of algae growth along leaf edges.
It seems odd that I should be battling algae in a heavily planted tank with good growth.
Might there be a connection between this problem and such extreme pearling? Thanks.

Well, it is the same amount I've had for several months: 55 watt @ 8hr/day over 29 gal, although I did put in a new bulb last week.