Some systems enable the farmer to agitate the storage directly with compressed air and separate air hoses. These systems of agitation are limited to relatively small storages or easily agitated manure. For larger storages, or for beef or dairy manure, a separate agitator will likely be needed. Where a separate pump is being used, perhaps to agitate the storage, it may be used to fill certain vacuum tank spreaders. Often, the spreaders have a hatch on the top that will facilitate this top-loading with a separate pump.
Most tanks have a method of indicating the level of manure inside the tank.
One common device consists of a float inside the tank linked to a pointer on the outside. This is useful both when filling the tank and when spreading manure on the fields. The vacuum tanks also employ an automatic shut-off valve. This prevents the manure level from getting so high that it will be sucked through the air lines where it could damage the pump. Table 1 gives some pertinent data relating to vacuum tank spreaders.