+1 for Tropic Marin Pro Reef. BRS has a few videos where TM Pro does well on many factors. Here are a few highlights. Pharmaceutical grade ingredients, mixes easily and no settling/crud buildup, water maintains chemistry over time, salt mix is uniform throughout container. Not cheap for sure, but just one less thing to worry about.
A lot depends on how you plan to mix and store it and how soon after mixing you plan to use it.
I use 50/50 IO and IORC and make enough to last 6 weeks at a time. It holds its parameters well in storage is why I like it so much. It wouldn't be my choice if I was mixing tank-side for a wc hours later.
Instant Ocean Reef Crystals. I used Red Sea blue and black but got tired of the higher price. I've had no regrets switching to IO and with the money I'm saving, I can buy more corals/fish.
Using fritz here blue box mostly because of the price. I was able to get 200gal boxes for 40bux each so i went ahead and got 6boxes. I havnt ran into any issues, mixes clear quickly, and is pretty stable to the parameters im trying to maintain. But i do like tropic marine, and red sea blue bucket aswell