Storing Saltwater

Craig Lambert

Premium Member
Randy,

I like to do small water changes daily. (I find it much easier). In my system a one gallon change per day equals 10% per week. I have seen threads saying you should leave a powerhead in stored saltwater. After mine has mixed for 72 hours I remove the powerheads and heater and leave it in a covered brute container in my garage. I make enough to last 7-10 days. Is there any reason to keep it circulating? I havn't been doing that.
 

Randy Holmes-Farley

Reef Chemist
Premium Member
I store raw, artificial salt water for weeks with no stirring. It need not be stirrer, heated or aerated, IMO. I too change water every day (1% automatically).

Raw artificial seawater is different than old tank water or NSW, where organics in it can degrade. You need to keep the latter two aerated somehow, or they can become anaerobic. :)
 

RichardS

Premium Member
Randy,

I noticed whenever I let my sw sit for a longer time (~week+) that the alk & ca are very low. You don't have a problem with precipitation storing it? Is there a way to avoid that?
 

Randy Holmes-Farley

Reef Chemist
Premium Member
I've not noticed that, but I also do not monitor it closely. There is some preciptiate on the bottom that is calcium carbonate. But I do not think such precipitation is dropping the values too much in a week.

What salt mix?

Add anything to it?
 

RichardS

Premium Member
I've noticed it on IO and also Tropic Marin back when I tried it.

No I'm not adding anything to it. Just DI and the salt.
 

Randy Holmes-Farley

Reef Chemist
Premium Member
There shouldn't be a lot of ongoing precipitation from dissolved salt mixes, but I'll try and monitor it some time. Anyone already do that?

What size drops in alkalinity and calcium did you see?
 

RichardS

Premium Member
It's been at least a year ago that I noticed that so I don't remember the exact reading I got. It was dramatic though, enough that I now always use my water within 48 hours of mixing it up.

I believe I checked Ca, dKH, and Mg and all were very low. Also I did not see alot precipitate in the containers, which I thought was odd.
 

Randy Holmes-Farley

Reef Chemist
Premium Member
Maybe it was a bad batch with excessive alkalinity to start. If you start with 4 meq/L (11 dKH) alkalinity to start with, the total of magnesium and calcium cannot drop all that much even if all of the alkalinity precipitates as calcium carbonate. Calcium could drop by 80 ppm if magnesium does not drop at all. Or magnesium could drop by 50 ppm if calcium does not drop at all. And that assumes the alkalinity drops to 0, which can't happen from simple precipitation.

Alternatively, all may drop if the salinity was reduced by addition of fresh water somehow.
 
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