Hello
With the KZ Coral System you can choose to dose all 4 bottles at the same time/on the same day if you wish once per week, or you can spread this out over 4 days. As long as they are all dosed once per week we don't think you'll see too much difference and the elements will be replenished each week regardless of the approach here. For those using this here at the office, they have opted all on the same day so that they don't forget to dose them.