As Crissy said, get as small amount of this salt for I too never heard of it and beware of salts saying anything as for no phosphates or nitrates. For on my twin eel tanks, I once switched too using Oceanic and on my eel only tanks, I only test every week the Ph and not so often then for nitrates. For on a 240 gal two tanks system, I do a weekly water change of 30 gals.
I back then only checked for nitrates in a rare blue moon and then I was shock by the nitrate level which I had then. The nitrates then was somewhere near 80 PPM and I look for the cause in this.
I retest the RO/DI water in which I the Kent marine four stage unit and I had added a fifth stage to this RO/DI unit.
The water was fine, I then figured to check the water in which I prepare for my water changes, I made the water as I always done at 1.026 and found that this salt had nitrates for the 30 gals water change I mixed had a nitrate reading of 60 PPM. The higher the salinity, the great the volume on the nitrates.
I then drove out to fish world in which they had a salt sale on the instant ocean, I brought the last six boxes they had and done a serious of water changes, and in just some 3 weeks time, the nitrates was at untraceable levels again.