Help- My stored SW in rubbermaid can has white sediment

[NaClFinatic]

I have a rubbermaid trashcan that I bought to fill with RO or mix saltwater in. I rinsed it with RO and vinegar when I got it then used a few fills to mix water to fill my tank, and a couple times for water changes since. I filled it two weeks ago and used half last week in a water change and was about to change the water again but it has some white powdery type stuff all over the can where the water was and on the mj1200 intake that was in there to keep it mixed. The water was always above 80deg and the Mj was in there to keep it mixed. The main difference is this time I just left the Mj in there and before I kept a Mag 7 on in there so it was really mixed.

My main concern is coudl this be something from the can that could hurt the tank? If it is just not mixed well enough and had a little settling of the salt and mineral I cna live with that. The Sg want high or low, It is still 1.025 as I mixed it originally. Anyway I already emptied my sump so I gotta make some water fast or use this. Thanks!!!

[CarmieJo]

I think that it is just mineral deposits. I have it on all of the containers I use for SW.

[lReef lKeeper]

same here.

[NaClFinatic]

Thanks! I was a littie worried but figured that must be it. I went with it anyway since I woudnt have a good mix of water till tomorrow.

[JeffDubya]

A question about this (and I have the same issue). I used to add salt to my RO make up water and then store it as saltwater. Now, I just store the freshwater and add the salt as needed. Which is better? If minerals are settling out in storage, then perhaps mixing it fresh is better...

[CarmieJo]

I think it happens pretty much right away. When I store SW it is in a Brute trash can. I also have a couple of totes that I will mix smaller quantities in but I never use them for storage. Both have the mineral deposits. I think that I read somewhere that sometimes the salt has more minerals than can go into solution and these will settle out.

[saltyreef]

Same here with all my buckets & the holding tub!

[JeffDubya]

Every now and again a put some diluted muriatic acid or vinegar in my buckets for a couple hours to get rid of most of the deposits, otherwise they invariably end up in my tank...

[Russel P]

Those chips in our mixing vats are composed almost entirely of Calcium Carbonate (CaCO3), with traces of magnesium. Salt manufacturers add anti-caking agents, mostly clay -so that the salt is less likely to clump. Synthetic sea salts are not made of evaporated seawater. If you took evaporated sea salt and added water, all of your animals would die. The dissolved minerals that are bound to each other in the solution break apart, then recombine with other elements when water is added back, and change the make-up entirely. All the salts we use today are still loosely based on the old McLachlan recipe from 1964.

There is no way to dissolve these calcium "chips" back into the seawater, since calcium carbonate doesn't really dissolve at the pH of seawater. But any going into your tank is perfectly harmless. At higher temperatures calcium carbonate precipitates more easily, which is why pumps and heaters tend to get hard calcium deposits so quickly
.
I personally don't keep a heater in my mixing vat for that reason, and I mix it in cold water. I typically change water on Sunday mornings, and add the heater when I first wake up. Another tip is to mix the salt vigorously -no salt clumps left sitting on the bottom! Also I use a powerhead in the mixing vat and keep the venturi valve wide open. Pumping air into the mixture keeps the pH stable, and expidites the mixing time. Also, I always add less salt than I need, and add more to get the salinity level where I want. There are way more precipitates when I've done it the other way around.
Hope this helps.

[NaClFinatic]

Thanks! So much good info in that post!