Yes Amazon or eBay. Any bag of unscented epsom salt will work for the 3rd part. Here’s an example:
https://www.amazon.com/Jacks-Nutrients-Formula-5-12-26-2-2lbs/dp/B07NLJ94WX/ref=mp_s_a_1_5?crid=2YYUUT2UWVI55&keywords=jacks+nutrients&qid=1639359416&sprefix=jacks+nutrients%2Caps%2C362&sr=8-5
https://www.amazon.com/Nutrients-Calcium-Nitrate-15-0-0-2-2lbs/dp/B07NLKS8C4/ref=mp_s_a_1_6?crid=2YYUUT2UWVI55&keywords=jacks+nutrients&qid=1639359416&sprefix=jacks+nutrients%2Caps%2C362&sr=8-6