Yes, provided, i) Light ingress and evaporation are minimized; ii) Shade or bury the reservoir to minimize nutrient temperature; iii) Avoid the use of sugary additives such as carbohydrates and molasses.  With a super-stable nutrient such as Veg-1 and its associated additives, batches can be stored for several weeks or even months provided pH is set well below 6.5 on day 1.  By keeping everything clean – reservoir, drippers, feedlines, pump and filters – System Maintenance will help ensure all plants are being watered properly.