I use instant ocean. A lot of other users like Reef Crystals made by the same company. But there are tons of salt options out there and im sure everyone has there own personal preference.
The only two I have used are Instant Ocean and Reef Crystals. I started with IO and used it for several years. Then on a whim I got a couple of buckets of RC to try. In a couple of weeks I noticed increased growth and never looked back.
I use Reef Crystals also. Never had any issues. I usually buy those $50 200 gallon boxes online. Last year I used a bucket of that Salinity from SC, it was awesome. I'd use it all the time if I was a rich person.