Alk precipitation in premixed salt

[FabioFavia]

I buy my saltwater premixed at the store due to convenience. The salt used at the store is Fritz. A month or so ago I started testing the params of the premixed saltwater before I do my water change. I noticed that the salinity was consistently at 1.024 but the Alk was in the range of 6 to 7 dkh on every batch of water I bought over a period of time, the calc was always in the 410 to 440, the mag was also in line with Fritz parameters. I imagine there is some precipitation going on from when the salt is mixed at the store to the time I use it. I usually will have a jug sitting around for a few days to a week before I use it, I keep it in a sealed jug with no circulation or heat at 72 degree room temperature. Am I safe using aquavitro 8.4 to raise the alk of the jug of premixed salt to my tanks alkalinity which is usually 8.7 to 9 dkh?

 

[Big G]

Some have noted that running an air stone before using has helped with some premixed saltwater's alkalinity numbers.

 

[Randy Holmes-Farley Verified Community Expert]

The salinity of that mix is a bit low and a 7 dKH at sg = 1.024 will jump to 7.7 dKH at 35 ppt (sg = 1.0264). So that's part of the issue.

Do you see cloudy precipitate?

I'd personally use baking soda if you want to boost the new salt water, but the Aquavitro will also be OK.

 

[FabioFavia]

I didn't see any cloudy precipitate at all. Thank you for your help Randy

 

[Randy Holmes-Farley Verified Community Expert]

You're welcome.

Happy Reefing.