The Large Deluxe Floating Chemical Dispenser is for use in larger sized pools. Simply insert the tablets into the dispenser and then regulate via the adjustable gate on the side of the unit to make your life easier and negate the need to always think - have I put chemicals in the pool today? The dispenser is to be left in the pool whilst not in use but we advise you must remove prior to swimming and leave out of harms way. Individual swimming pool requirements are different for chemical dose rates so you will need to establish for yourself what gate setting to have open in order to sanitise your pool sufficiently.