Probably be better off with two or just one 12KG.
I bought mine local and last time I was there I remember seeing a few more in the warehouse. Kinda surprised there's not more online. Widely available in the Middle East and Asia though?
I wonder if this is something that got caught up in buyouts of the indoor garden industry and production was cancelled? I know when Scotts/Miracle Grow, AKA Hawthorne, bought out major brands like General Hydroponics, Gavita, Sunlight Supply, Hydrofarm, and others we lost a lot of good products and those that are gone are getting harder to find, usually sitting on a back shelf of a shop somewhere collecting dust.