can i keep my salt water in my 5 gallon jug for a week ? or should i just make a new mix the next time i do a 10% water change? if yes how do i keep the water good and fresh
As BIGgourami stated you can keep it for weeks. I like to keep the water circulated with a powerhead or pump to keep it "good and fresh" while in the container.
If you don't circulate it just remember to agitate it well before you add it in. Otherwise there won't be as much dissolved oxygen in it. So either a powerhead before you add it or an air pump with an air stone would work too.