Hi all, trying to get Faintly Humming Sea Stones (Scrying Stone to get sandcastle and for the achieve) off Mrrl, and have my currencies, but Mrrl is only showing me one item which is Curiously Warm Kelp Bundle.
Do I have to unlock something to make him show me more stuff?
Not 100% sure, but I was under the impression he only sells one item per day and it’s random. I found the best way to get scrying stones was just to go around killing rares, and also doing the Mardivas weekly.
Ty for reply, when the dailies reset and he had a different item for sale, the horrible truth dawned on me lol! I don’t think I have the stomach for the back-and-forth collecting of the items that only last a day. 
So gunna give this one a miss.
Once you purchase the purple final product, it lasts forever. And you don’t keep it anyway; you “use” it to unpack what’s inside it. (It’s basically a container with a specific bit of loot.)