KNO3 aka potassium nitrate aka saltpeter. Check with a butcher that makes sausage. They might have a bunch of it on hand. Check with a good drugstore. Check a large garden/farm store. In some countries it's hard to obtain because in a stretch it can be used to make low grade explosives.
Not sure on the potassium sulfate. Check with a garden center. In fact check with commercial orchid growers. They just might have what you need.
Not sure on the potassium sulfate. Check with a garden center. In fact check with commercial orchid growers. They just might have what you need.