These two are similar and so good I take both! But only tablets sourced from commercial supplement companies in the West. These are too expensive in Thailand due to import duties, so where can I buy local produce? I know there is a spirulina farm in Chiangmai, but where are their retail outlets? Many thanks!

One retail outlet is the health food store Ban Suan Pak in Chiang Mai which sells local spirulina in powdered form 150g for 225 baht.