Salt won't dissolve

My salt has never done this before. Ive mixed it with a power head for hours and it won't fully dissolve.
The water is not cloudy but full of tiny white particles. I always mix for 24hrs with a powerhead but its never looked like this after a few hours. Usually there are never any particles. Calcium carbonate maybe?
I'm almost finished with my 5 gallon bucket of instant ocean so buying new salt is not a big deal.
Should I finish the bucket or buy new?
If I should buy new salt what would you recomend? I have tons of softies but bought my first sps today.

 

Salt mix separates out so you may have calcium carbonate in excess and it won't mix in the change water, it should dissolve in the tank though.

 

Is this something you mix water in frequently but don't clean regularly?

 

Yes...but i also mixed a second batch in a 5 gallon bucket that is only used for top off and it did the samething.

 

Ok, so there's no problem with using this mixed water after 24hrs :relieved: but why is my mix doing this now and not ever before?

 

Are you heating the new mix to tank temp?

 

Did the top not get sealed the last time you used it? I'd imagine if the salt got moist from humidity in the air, it could end up forming calcium carbonate before it ever got mixed in to a bucket of water.

 

This is definitly possible. Plus the humidity here in OKC is tropical level right now. Weatherman said dewpoint is 75 degrees and never reaches above 80 anywhere in the world.

 

Yes I'm mixing with a powerhead and heating for 24hrs prior to performing the water change. I heat to around 79 or 80

 

I use a large whisk and mix the water well before putting my powerhead to use.