I found it didn't mix well, staying milky for days. Lots of complaints at the LFS about it too. Left residue in my bin, and adding it to the tank annoyed all my corals.
I posted about it at the time, and a couple people were like you, thought it was great, so either you're all crazy or the salt is inconsistent. I'm guessing the latter. Either way, it was more money, and I saw no benefit to using it. If I'm going to spend more money on salt, I'd use Reefers Best.

I have never heard anyone hating one it ever until now. But I would not trust the guy that would choose io over salinity

Look up our last salt use poll, lots of us untrustworthy people there -lol

How many have tried more than the cheapest salt? Io is great when paired with dosing.

I used Reefers Best for 2 years, then moved to IO with 25g Ca, find the same results with both. Over the last 15 years, I've tried most, and always go back to IO.

Had big issues with dirt in the bottom of my mixing container with the fluval. 2 buckets in a row there were brown chunks floating and murky water when i cleaned bin out after.

Might just go back to IO or try D and D next.

Thanks I appreciate the input. Thats pretty odd though. I didnt see any of sort of brown particles in my mixing container. But I will certainly will be keeping an eye out.

Had a bad problem with the residue from the Fluval salt. Plus floaties looked like GFO floating on top of water. Not sure if it was a bad batch but my storage tank turned black. So much so that Hagen is looking into it for me. IO is filthy but this fluval batch made it look clean.

Well so far nobody has anything good to say about the fluval so really I have no need to use it. I will continue to monitor the bag I have and after that will look into other salts. Why do you say IO is filthy? What are the majority of people using then?

Salinity is a very controversial salt. It works great for some (like in my case) while it worked like the worst possible salt (like in Brad's case). I myself is going to move to H2Ocean (seems like the most stable salt with a nice price being a high end salt) since its parameters are much more stable from buckets to buckets unlike Salinity which has a tremendous deviation between buckets (infact, I exchanged my 2nd bucket for a new one at LFS since the mg was way too low - funny!). IO is possibly the most appreciated salt in this hobby since one way or the other, you will have to dose the tank eventually. I just don't like to dose freshly mixed salt so don't use it. And since I usually get flamed for using "less expensive" products (with "you get what you pay for" motto), I try to give the best salt to my tank - the ONLY important thing for this hobby ;)