too much light?

[caoder]

2 cfls in a modified hood 13 + 23w aylight bulbs. too much light for a 16g? it 18" deep with about a 24 x 12 footprint. its dirt capped with sand with h. polysperma, ludwigia repens, and some salvinia mixed with duckweed. There's hair aglea growing all over the ludwigia and i had a fish that disturbed the cap throwing dirt all over the tank a while ago which caused a nitrite spike. i was wondering if i should go with just 2 13w bulbs or 23 w bulbs.....