new salt mix good to use?

[banditpowdercoat]

I have had water mixed for a month and all is good. In rubbermade buckets. Just circulate for a few hrs before changing. I always make up 15g of change water before I go to camp for 3 weeks. Incase something happens. Then when I come home, I do a WC with it, and make a new batch. Usually its made for 6wks as I do a 15g change 1 every 6 weeks when Im home. Mind you, I am a FOWLR tank basically.