Henry,

Below listed company can sell you powdered chemical and you can mix your developer , fixer combinations after you learn the recipes from google and APUG. Some chemicals are dangerous when inhaled , some less. You can always get help from experts at the forum about mixing , storing. I bet its a high heat climate and there must be tropical formulas for you. Contact with company and ask their help.

ADISOL, is an Ecuadorian company dedicated to manufacturing and marketing of chemicals for industry, import of raw materials and technical advice for the treatment of industrial water and wastewater.

www.adisol.com.ec

Good luck,
Umut
Istanbul