With the same visualization equipment it was observed that upon decreasing the flow the meniscus (green) retreated but the colloids (dark blue) remained in place on the grain surface. After increasing the flow rate to the same rate,the menisci did not come back to the original position and the colloids remained in place. Only after increasing the flow rate several times the meniscus snapped back via a Haynes jump to the original position and swept the colloids away almost instantly. In this case the colloids changed the pore geometry sufficiently so that the water followed a different path with the same flow rate.