Ich's alive!???

It very well could be salt that never fully dissolved and you never noticed before. Freshwater parasite cannot live in saltwater. That is why you add salt and increase heat. The same treatment can also be used for velvet. Velvet and Ich can be brought on by stress, overcrowding/over-feeding, as well as temperature fluctuations.

As others have said, allow about 2 weeks before adding new fish.
 
It very well could be salt that never fully dissolved and you never noticed before. Freshwater parasite cannot live in saltwater. That is why you add salt and increase heat. The same treatment can also be used for velvet. Velvet and Ich can be brought on by stress, overcrowding/over-feeding, as well as temperature fluctuations.

As others have said, allow about 2 weeks before adding new fish.
I used API aquarium salt that has an entirely different look, and made sure it was all disolved in buckets before adding it. Also, it's been more than 2 weeks since I've added salt, so whatever miniscule amount that might not have fully dissolved in the buckets before being added would certainly have dissolved by now. I can't see any way it could be salt... though I would prefer that was it so I could have some closure.

I've already allowed more than 2 weeks for treatment, so I'm not sure the reasoning for waiting another week (though I'd rather be safe than sorry)??

So... wait another week or so, performing regular testing and perhaps 2 partial water changes per week (doing my best to scoop out whatever those specks are) and then if all appears well start adding fish?
 
What type of substrate do you have? I have sandy gravel, and there are pieces so tiny that they're light enough to get sucked about halfway up my gravel vac. They kinda hover there in the tube for a little while, but then eventually sink back out into the tank. Because my gravel is light colored, these particles definitely do look like grains of salt. I used to blame it on the fact that I didn't rinse my gravel well enough before putting it in the tank, but probably most gravel has similar particles in it.
 
What type of substrate do you have? I have sandy gravel, and there are pieces so tiny that they're light enough to get sucked about halfway up my gravel vac. They kinda hover there in the tube for a little while, but then eventually sink back out into the tank. Because my gravel is light colored, these particles definitely do look like grains of salt. I used to blame it on the fact that I didn't rinse my gravel well enough before putting it in the tank, but probably most gravel has similar particles in it.
It's Estes Natural gravel... smooth, good sized pieces for the most part... with none as white as the specks I saw... or as small. I made sure to wash it very thoroughly when I bought it, but perhaps the specks are just from the gravel.
 
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