Salt not disolving completely?

[ScorpiosWife]

Hey guys. Today I did a big water change in my puffer tank & of course, added Instant Ocean to match the salinity they're currently in. It doesn't seem to matter if I change out the water 5 gallons at a time or 30 gallons at a time, there's always a gritty mess at the bottom of the bucket or tank when I'm done. Doesn't matter if I leave it sit for an hour or a day, it's still there, undisvoled. What is this & why isn't it disolving?

[CRUSHER]

must be calcium chunks?

[rage]

Hey guys. Today I did a big water change in my puffer tank & of course, added Instant Ocean to match the salinity they're currently in. It doesn't seem to matter if I change out the water 5 gallons at a time or 30 gallons at a time, there's always a gritty mess at the bottom of the bucket or tank when I'm done. Doesn't matter if I leave it sit for an hour or a day, it's still there, undisvoled. What is this & why isn't it disolving?

If the salt is allowed to get wet or has been exposed to humid air for some time, some of it can turn insoluble. Instant Ocean is known to do for some people.
I have had the same problem sometimes, always with IO and mostly with old bag of salt that had not been sealed tight.

[ScorpiosWife]

The bag is nearly a year old now & was stored under the aquarium with a chip clip, so that's got to be what it is. I'll just do what I always do. Get my super mesh net and get em out!

Thanks guys!