I've used IO for 15 years with zero problems. I tried a pail of Seachem once and my tank went for a crap for that time period.
I'll also add that i'm a very lazy reefer. I've never rolled my buckets and quite often when i'm making up my salt water I only mix the water for 2 mins max.
I have a mixed reef with mainly SPS.
Here in PG a pail of IO is $69 and at one time I paid $119. I have pics to prove