The finer the sand the higher the potential for it to get sucked into filters... I use Pool Filter Sand exclusively as it is coarse grained...
The impellor is the part of the filter that is vulnerable to sand. Most canisters intake water, pull it through media, then past the impellor, then push it back to the tank. In this series the sand is filtered out by the media before it has a chance to affect the impellor. Thus most canisters aer far less vulnerable to sand than other filters. Power Filters, for example, pull water in, run it past the impellor, then push it through media. This series makes a filter very vulnerable to sand.