Fresh salt water mix...how long will it last?

[arejayy]

I would like to do small, daily water changes on my 34g tank. I was thinking of mixing up 5g and taking out 9 cups or so a day to change out.

My question is, will the 5g of mixed salt water be ok sitting for 7 days? And is there anything I need to do to keep it fresh and ready to put in the tank? Thanks

[bertoni]

If the mix doesn't have any organics added to it, the saltwater should be fine for a very long time, months or years. :) Just replace any evaporated water. If the salt has some added vitamins or other nutrients, a small pump might be useful to keep the water oxygenated.

[FranktheTankTx]

Ya. How long is it good in an aquarium? lol