Keeping RO/DI water

[summer6]

This is new for me so this may be a really silly question...I'm going to buy an ro/di unit and would like to use it for water changes and sump top off.
How long can I keep the "clean" water stored in a holding container?
Also, once the saltwater is mixed can it stay "fresh" for only about 24 hrs. with aeration or longer?

 

[virginiadiver69]

My understanding is that it will last longer than you would be storing it(if that makes sense). Several weeks if not more. With a 200 gal tank your top off amount will probably keep you going through your "stock "pretty quickly. Just keep it covered.
My LFS guru tells me that "aeration is not necessary, but won't hurt anything". You will get a lot of salt creep on your storage container lid if you do though.

 

[alan214]

It may not be necessary, but I always keep a powerhead running in my storage container. You should be able to keep made-up SW as long as you need to.

 

[summer6]

Thank you both for the info. I was hoping that holding time wasn't a problem with stored water. My thought would be to cover it and use a small powerhead, but I'll also see what my LFS would say because salt creep is a pain.