Auto watering for soil build help and Rez nute questions

Hi gang, if you cats don't mind I've been kicking around an idea to build a small gravity self watering system. I have most of the parts and am thinking using a 5gal bucket as a Rez, shut off valve at the bottom and hooking up a micro irrigation timer from that "I have many" . From there just running a line and getting a water ring. This way I can set it up to water every two or three days when I get busy.

Question about nutes. I'm using natural in soil "earth juice lineup". If I mix up 5 gal and run an air stone won't the nutrient go bad before its used up ? I may run a coco mix after I get threw the FFOF I have.
Thanks much for any info !

Just throwing this out there, I'm new to the nutes, my Canna nute solution stays good for at least a week with air stones. I have no experience with earth juice.
As long as it smells sweet & not bad, should be ok.