Automated Water and Nutrient Filling for the Reservoir of a Kratky Hydroponic for Pak Choi (Brassica Rapa Subsp Chinensis) Cultivation: PENGISIAN AIR DAN NUTRISI OTOMATIS PADA RESERVOIR HIDROPONIK KRATKY UNTUK BUDIDAYA PAKCOY (Brassica Rapa Subsp Chinensis). at 2025, 18 (2), 98-107.