Keep the biomax and only rinse with tank water. It is basically just rock and replacing it is not necessary. Rinse/squeeze the foam filter block at least weekly (go ahead and rinse the carbon then too but DO NOT rub it together as it just breaks it down). Swap the carbon out every 2-4 weeks. A lot of people replace the carbon with a bag of chemipure blue. I like that or a bag of carbon with a pinch of GFO.
You can rinse the foam filter in tap water in the sink. As long as you have sand and rock (a cycled tank), it doesn't matter that much. You can also rinse/squeeze it during water changes with tank water if you'd like. However, the intank media baskets are a bit nicer if you want an upgrade.
Keep in mind that the foam filter block collects crud, food, waste, etc., and that rinsing it is the only way to remove the crud to keep it from breaking down in the tank (think of it like not taking out the garbage for a while and things beginning to rot in it).