I hope it was free.
first its an orange paddle sponge (Clathria sp.) not a tree sponge of any sort.
and its dying. the haze of grey is dead tissue surrounding the inner live part of the creatures.
the purple look to the top is cyanobacteria smothering it and feeding off the dying parts that it is smothering.
sorry to be the bearer of bad news but you have one sick/dying sponge.
if you havent purchsed it DONT, if you have take it back and throw a royal fit for being sold a dying animal.