Question: 30gallon tank, 30lbs of flourite...and that's your ONLY substrate?
If so, that's not enough. You want at least 2.5" of depth on your substrate for the plants to have enough rooting space.
I've found that 2lbs of substrate per gallon of standard rectangle tank is usually about right, gets you close to 3".
Thus, shallow tanks with a bigger footprint need more than 2lbs per gallon, and tall tanks (especially hexagonal tanks) need less, since they have less area to fill with gravel.
Former advisor and planted tank geek...life's moved on though.