yote, your were right about oceanic. i bought a tub yesterday. this stuff is awesome. it mixes allmost instantly, there was no undesolved crystals in the bottom of my mixing bucket. i have let instant potion mix for 24 hours and there were still crystals in the bucket. my calcium was at 420, ph 8.2 and alk was at 10. straight out of the bucket! no more dosing new water! whoo hoo! it's well worth the extra 5 bucks for the oceanic if you don't have to dose anymore. this is definitely the salt i will be using from now on. oh, by the way with instant potion my calcium was at 320, and ph was 7.8 in a fresh mix.