How long can mixed saltwater be kept? Indefinitely in a closed container? Can I just mix and aerate it thoroughly prior to use?

First post...lot's of questions...

Welcome! Dont be shy with the questions!

I have kept SW in a Rubbermaid Brute with a lid for weeks with out noticing any issues, I dont know that I would keep it for a really long time, because even sealed, it will deteriorate slowly. What point it becomes unusable is anyones guess, but why take the chance?

Thanks poppin_fresh!

Before I get an RO I may be buying my mix from the LFS.

Hey mickster and :welcome: to TR.

I keep mine for a few weeks in a Brute, kind of making it up, using most of it, adding some more fresh and then starting over. I have found that if I don't empty it totally and rinse it out after 6 weeks or so the sides of the container start to get gunky looking. This may not be harmful but, like Jon said, why chance it?

Where are you from in NC?

Hey CarmieJo!

I'm in Charlotte. Transplanted from NJ about 10 years ago.

We moved here from OH back in 86.

he he this ones interesting....

I used to keep a 32 gallon brute handy with a powerhead and heater dropped in (along with a pump to the sump for nice fill automation during water changes) up until last weekend (Switched to a 25 gallon rubbermaid). Since I do 2 * 5 gallon water changes weekly (thursday and sunday) the 32 would hold 3 weeks worth of SW, I switched to a smaller container originally because the brute sprung a leak and well... heres the other reason!!!

By keeping my W/C water heated I could introduce it to the tank without fear of heat shock... originally I had this heater switched and would kick it on the morning of each water change but decided to let it run all the time... silly me. Imagine my suprise when the salinity of my water change source jumped way up!! If I didnt have a habit of checking it periodically I would have never noticed... one week of heat and it had evaped out quite a bit, so smaller more airtight and sealed container (less water standing) and heater back on the switch for me. Routinely refilling it every two weeks is still not a large deal and plans are in the works to plop an RO feed into the tub with a float switch (and a master valve) so that I can mix the salt and such all in one (right now I pre mix in 5 gallon buckets and pour in).

Regardless I think SW sitting for a short few week period is not a huge ordeal, the biggest problem I see is evaporation and salinity change!

Joe, I do check the SpG before I use the water for that very reason. Great advice!

Heres one for the crowd, anyone know how long natural sea water can be kept?? closed container

I know I have read of people storing it for weeks but I have no personal experience.

I have a 32g rubbermaid trash can with lid that I use for NSW. I have a mag pump that keeps it circulated and a heater to maintain a constant temp so it is ready to go when ever I want to use it. With the exception that others mentioned also. Salinity check. I keep the heater in it as I sometimes use a lot of SW due to my feeder tanks and do water changes often. After I collect my SW, I will let it sit for a few hours to let any materials that may be in the water to settle. I then pour off the top and leave about an inch in the bottom of each container. Pour it in the 32g holding can and I've kept mine for up to 2 weeks. I prefer to dump the last 1/2" to 1" out when I'm done with the NSW to be on the safe side as it is NSW and I don't want unwanted organisms possibly growing in/on the can as it is more fertile than premixed SW. (NSW is living water and full of organisms)

Dick was kind enough to guide me in this and get me started last year because of my easy access to NSW and he will be able to tell you exactly how long one can safely store NSW I'm sure. It's what he uses in his tanks! And we all know what a beauty she is. :agree:

ahh good point skurvey! I also avoid draining my tub entirely and dump out the bottom bits. Though I'll typically refill before completely empty. I'm using a maxijet 1200 to pump out with a foamy on the end to keep particulate from being sucked in.