Short answer: mainly because plants take up nitrate, and alkaline water keeps pushing pH up. Both are normal. A gradual rise in a Kratky container is usually not a problem unless plants start showing symptoms. Nitrate uptake Most hydroponic nutrients supply nitrogen...
Short answer: add a small amount, stir, wait a few minutes and test again, repeating until pH reaches about 5.5 to 6.0. UF/IFAS notes that white vinegar typically takes around 2 teaspoons per gallon, depending on the water. Your options White distilled vinegar. Cheap...
