Question

how much water does the plant wolffia globosa require per day per 1000 specks?

Answer 1

Wolffia globasa has a large number of specks floating on water . They are the smallest plants.   The diameter of a speck is approx: 0.2 mm.

Its volume:  4/3 * pi * 0.1^3   mm^3 = 0.00419  mm^3

A thousand of them probably need:  around 4 mm^3 per day or 0.004 cc