Not sure where you are located geographically, but in cooler fall weather, you should be OK. Sunlight (UV) and heat are what really kill your mix fast. Keep it somewhere shaded and cool. I would also head to the hardware, farm, or home store and get a 2-3 gallon jugs of 12.5% SH pool shock. You will have enough to tune your mix up if you feel you need it. At a farm store you can usually buy a 5 gallon pail of 12.5%, it will be back by the "real" ag stuff like the cattle prods and cow tags. Farmers use it to sanitize barns. You'll pay like 5 bucks a gallon. The good news is when you are done with it, you can refill it with SH and transport an extra 5 gallons at a time in a properly labeled container. I don't need them so much anymore, but I always have a few of those buckets on hand.