expiration on mixed SW/

[pipermurphy]

Is there a general agreement on how long you would keep mixed SW before pitching it?

I have some water that was mixed 2 months ago, it is in a tight 30 gal container with a 25 W heater & PH in it. I have not touched it since I mixed it up and the SG was set for my tank. Would it be okay to use for a 30% water change.?

 

[darb2]

I usually only keep mixed sw for less than a week. I don't think is "goes bad" but I would check all parameters before adding to the tank