Hello,
I think you can buy Seramis easily over the Internet. So I e.g. also get Kanuma.
I use very successfully for decades Seramit for windowsill culture of Paphiopedilum, Phragmipedium, but also in the Sämlingsaufzucht, eg Cypripedium.
I have some orchids in hanging baskets bar. Normally the window to dry out quickly. The trick, an old sock filled with Seramis in the middle of the basket.
All around normal ground orchids. So I use Seramis a) if I want that everywhere in the pot, there is the same moisture and
b) if I want that the substrate is not as fast drying and c) if I need a sterile substrate with good water management that is still well ventilated .
Greetings
Bernd