Previous Conclusions:

	Additives like BaSO4 or SrSO4 can provides seeds for cristalization for PbSO4 crystals.
	In the SrSO4 case, due to his close similarity in latice parametes with PbSO4 the PbSO4 crystals will start to crystalize earlier than in the BaSO4 case
	PbSO4 crystals formed on the SrSO4 are more difficult to disolve in the reduction phase