You can continue to follow the APFUK recipe if you wish, and just source the salts from elsewhere:
Magnesium Sulphate (MgSO4)
Potassium Phosphate (KH2PO4)
Potassium Nitrate (KNO3)
All those links are for APC Pure who I know have good products and service, but you can probably find them cheaper on eBay, and there will also be options from Amazon or other online sellers.
Magnesium Sulphate (MgSO4)
Potassium Phosphate (KH2PO4)
Potassium Nitrate (KNO3)
All those links are for APC Pure who I know have good products and service, but you can probably find them cheaper on eBay, and there will also be options from Amazon or other online sellers.