In the first use, fill the Siliphos water softener dispenser all the way to the top.
Every 3 - 6 months, when the level of the Siliphos spheres went down about 1/3 of the way, refill to the top.
Personally, every 12 months or so, I take out all the Siliphos spheres and clean the dispensers' filter container. Just to keep it extra clean. Not a complicated or time-consuming task.