Welcome! Something like this?
https://www.pondxpert.co.uk/tripleaction-evolve-6000/p2979 How long has it been set up?
Frequency of cleaning depends on how much debris and load your pond has. Keep an eye out for reduced water flow, which would be the first serious indicator of cleaning required if you are not going to do it on a schedule.
Main thing is to keep the biofilter active as possible by rinsing the sponge and bio filter media in the pond water. I scoop some in a bucket and squeeze and rinse the foam in that and then discard the dirty water on the garden plants.
Zeolite can be recharged in brine water
https://pacificwater.com.au/product/zeolite-granules-media-bag/