The swirl & dump maintenance is the same with Version 10. The flow rate through the filter will slow down over time as the biolayer develops and suspended solids are trapped in the upper layer of the sand. Users will know when the "swirl & dump" is required because the flow rate will drop to an unacceptable level.
Higher turbidity levels will plug the filtration sand layer more quickly. As such, maintenance will be required more often to ensure a convenient flow rate for the user. It is recommended to use a sedimentation method if the source water turbidity is greater than 50 NTU. Acceptable sedimentation methods include settling the source water in a bucket before pouring it into the filter, natural or chemical coagulants or straining source water through a cloth filter.
