Storing a High Salinity Solution for Mixing SW

[maxtek]

I have a new auto water change system that will last me about a month between batches of saltwater. I’d prefer to mix saltwater more like twice a year, so I was wondering if it’s possible to keep reef salt mixed and in suspension at a much higher salinity so that I can automate mixing the intermediary batches.

Put differently, what is the highest salinity solution I can make with reef salt that stays in suspension for storage?

-Max

 

[ndrwater]

All salinity should stay in solution once mixed. I keep saltwater mixed for about a month with no real problems at all

 

[maxtek]

All salinity should stay in solution once mixed. I keep saltwater mixed for about a month with no real problems at all

Even if I mix it to 70ppt or 105ppt? I read somewhere that if it’s too concentrated the calcium precipitates.

 

[ndrwater]

Calcium can precipate out. Curious as to why you would want to mix water at such a high concentrate. I know that I have made mistakes in the past with which barrel I was pulling/adding water from.
Why not just mix at the usable concentrate of 35ppm? Seems easier to avoid potential mistakes and eliminate the precipitation problem

 

[maxtek]

I do that, in fact, 65 gallons at a time. With a continuous water change, that lasts about a month. The goal in this next phase is to try to engineer a way to automate mixing the 65 gallon batch by pumping a stronger brine from another barrel — the salt concentrate — back into the 65 when its empty and adding RO until it’s at 35 ppt.

 

[ndrwater]

Gotcha...
IMO, you may be over complicaring things, but I'd be interested in hearing how things turn out.

 

[NY_Caveman]

If @Randy Holmes-Farley stops by, he may know at what Salinity level the precipitation would begin.

 

[Randy Holmes-Farley Verified Community Expert]

I agree that this is not generally a good plan. Hypersalinity boosts everything, including calcium and alkalinity (and, less obviously, pH). All of these things will tend to cause precipitation of calcium carbonate.

If it is a low alk mix, or if you make it so by acid addition, you can likely get away with some salinity rise, but often it won't work, and 3x normal is not likely to be a good plan.