I currently use IO, but have used Kent, Tropic Marin, Reef Crystals, Coralife, Aquacraft, and Crystal Sea Marinemix all over a 10 year period.
They all worked great except the "CS Marinemix" which had a noticeable negative reaction on the fish and corals, in addition it was cloudy & dirty stuff; one fifty gallon bag was enough for me.
