I will start out by saying I'm no expert with salt
I only go by how my corals react .
IMO, almost any quality salt works as good as any other quality salt.
I often change to what brand is on sale for my reef tank.
I've only noticed a problem with 2 brands,
I think one was Oceanic, (comes in blue buckets)
I had cyano growing after the switch for 2-3 weeks
the other was some POS salt that had ammonia after mixed.
I personaly have had no problem with
I was just reviewing one of Jason's (aka squidviscious) reports here and stumbled upon this.
Apparently 'Instant Ocean' seawater lacked the element Strontium; in the absence of which proper development of the statolith in cephalopods was prevented. The squid were referred to as 'spinning cephalopods', as balance in the water column was not possible, and they were unable to capture food, in addition to having abnormal embryo development (Hanlon 1990).
Now I'm not familiar with these artificial salts, and 1990 was a few years ago and the problem may well have been remedied by now, but if anyone has a packet of this 'Instant Ocean' I'd be quite interested in finding out whether Strontium is identified as one of the trace elements.
Jason's ref is (so I hope he has these details correct!!):
Hanlon, R.T. 1990. Maintenance, rearing and culture of teuthoid and sepioid squids. Pp 35-62 in 'Squid as experimental animals'. Gilbert, D.L.; Adelman, W.J.; Arnold, J. (Eds). New York, Plenum Press.
Here's an interesting link for analysis of salt water. The poll shows that over 50% of people responding used Instant Ocean. (I've always used Kent myself) Anyway, there are tables comparing the various mixes.
and links to articles and other discussions.
went and had a squiz as promised........no contents listed on the box!!!! Just as well Nancy found the contents list elsewhere!! BTW if you use it seal the container! ours has turned to liquid on top and solid on bottom....we forgot to reseal the packet properly