From the above, it stands to reason that gels formed in lower concentration solutions may adhere more strongly to the channel walls. Furthermore, bulk rheology suggests that gels at low polymer concentration or low crosslinking concentration are weaker than more concentrated gels . This may explain the larger increases in ∆P found at low C Alg and low C Ca 2+ : the viscous shear forces of the fluid passing by the deposited gel can deform the gel easily without pulling it from the wall. This understanding may be further developed by measuring the rheological properties of the gels in situ. in situ rheological characterization of the gel would also reveal its mechanical response in flow, as bulk rheology methods are not sufficient to distinguish the dilute gel from water.