Undissolved salt in new aquarium

[deeze]

I'm finally filling my 70 gallon tank and my brother gave me some salt he had from about 2 years ago when he had a marine tank and about 5% of it will never dissolve. The salt was in a big sealed bag from Instant Ocean and looks very white and pure. It just keeps floating around in the tank. PH is good, temp is around 80 deg., and everything else seems ok. Any ideas on how to get it to dissolve or remove it?
Thanks,

 

[22caddy]

Just curious but did you measure the salinity? Unless the water is completely saturated with salt, it should dissolve. I am not sure about using salt that old. If it was sealed I would think it would be ok.

 

[deeze]

right now it's only up to about 1.016 and I stopped adding. It is quite stubborn so I guess I'm going to throw it out and siphon the granules out tomorrow. It's a shame because you know how slow RO water is, it's precious.
I stopped all the pumps I was using to keep it mixing because the waters getting ready to reach the overflow. Should settle to the bottom by tomorrow.

 

[lefty]

I've noticed that my IO salt doesn't always appear to dissolve right away. Give it some time, and if it still isn't dissolving, then perhaps there was something wrong with it.
-lefty