Can you post all the writing on the bulb, and look on the package for more info?
I do not see how anything purchased at Wal Mart is going to be good for a planted tank, and I agree with the above, highly likely low light or very low light. Not going to grow plants unless the tank is next to a window, then it is the window, not the light fixture.
I have several tanks that are 4' long (I am assuming your 55 is a standard tank) but none of mine are as tall as a standard 55 gallon. Mine are 16-18" tall. 45 gallons.
I run 2 bulbs, T-8, 32 watts each over these tanks. Each bulb is 4' long, and there are DIY reflectors over the bulbs. That is low light. If we were still going by watts per gallon I have 64 watts over 45 gallons. Just about 1.5 wpg. Now add in the light that comes through the window.
Over my 72 gallon tank, 2' tall I have 4 of the same bulbs: 4 x 32 watts over 72 gallons. That one also is low light.