In the end, it does not matter what is used, as long as gas-exchange takes place in a sufficient level, the substrate holds enough water to keep the plant happy between watering, retains some nutrients after fertilizing so the plant can take it up, and has a certain level of stability.

I have checked now with my friend that gave me the bag with that fantastic substrate that looks like crushed bricks. The product name is Seramis and are indeed a type of expanded clay shale. The colour is different from the product lb uses. It is very porous, but a lot smaller pores than crushed leca balls. It performs very well in my conditions and care.

Now I just need to find a way to get a bag to my country within a fair cost range. Thanks for waking this topic up!

seramis is one of the alternatives I found for kitten litter. It is uglier though; bright nearly orange and a lot more expensive. Available in every supermarket here it seems, as part of their plant substrate. This year for the first time I could not get kittylitter and bought a big bag of it.

Yes, I know. Widely awailable south of Denmark in basically all big box stores. But nowhere to be found north.

Expensive is of course relevant but also relatively. According to my investigations it is priced around you at approximattely half the price of acadama and it is in my experience, climate and care a much better substrate.