Hi there, first time poster here but I've been following the forum for years - what an outstanding resource! Thanks to all who contribute. Hopefully one day I can add my 2 cents. I have a general question (more of a curiosity) that arose from an observation at work. It has sparked a debate amongst my co-workers which I am hoping to settle. The ultimate question is whether or not the size of a column of water has an effect on the solids which have settled at the bottom. The debate has come from observing flocs of tiny iron particles settling out of containers of water. The mixture typically settles to approx 1/4 of the initial bulk volume. For example, in a 1 L container, after settling the solids on the bottom are roughly 250 mL with 750 mL of clear water on top. Someone suggested that in a larger container with more of the initial mixture the weight of the extra water on top of the settled particles causes them to compact tighter, thus changing the relative volume proportions (say 1/5 solids & 4/5 water). Does this make any sense? To me it doesn't because the mud at the bottom of the ocean would be rock hard. Does the actual quantity (volume) of water you start with really have any bearing on the final outcome? Would the shape of the vessel (tall and narrow vs short and wide) have any effect? Why do people prefer to decant supernatant from tall and narrow vessels? Do the particles settle any faster? I always thought particle settling was dependent only on buoyancy, gravitational, and drag forces. I remember calculating pressure at various water depths in my education but does that pressure have any effect on the compression/compaction of the solids? What determines how close the particles get to one another or how much water stays between them? At this point is it more of a particle-particle interaction? We can assume that in each case, the ratio of iron to water in the bulk (mixed) solution before settling is the same. Any input would be greatly appreciated!