storing ro/di water
 

can i just keep my ro/di water in my 5 gal container i bought at the fish store? it doesn't always have to be "fresh" does it?

Just as long as it's closed it should be fine.

I normally keep a powerhead in mine to keep water circulating..

In a closed container it lasts forever and a day. The only reason you cover it for long term storage is to keep dust and light out. The latter can provide stimulus for algae growth. If you use it after long term you will want to aerate it as Norton does.