I know some of you use ESV's B-Ionic salt system. For those of you who don't... It's a four part salt mix. Two dry, sodium chloride and magnesium sulfate, and two liquid, part A and B. This is my first experience with it. When I opened the NaCl bag I was a little discouraged. There were lots of lumps! Big lumps! This is usually the kiss of death with most all-in-one salt mixes. I gave it a shot anyway. About two minutes after dropping it into the RO/DI there were no lumps. It was completely dissolved! The water was clear!! Same thing with the mag-sulfate! In fact it might have mixed even faster. It's completely mixed by the time I measure out the A and B parts. So in the time it took me to measure out the parts, it is mixed. There seems to be no precipitant like my previous salt. When Craig Bingman spoke about reef chemistry, he mentioned you should mix the usual salt mixes before using because they settle out. Now that seems like a BIG pain. I never did it. Now there is no need to do that - or feel guilty about not doing it. Lastly, the old salt was very dusty. I wore a mask because it irritated my nose and lungs. ESV doesn't seem nearly as dusty. So that's the upside. What's the down side? No endless supply of plastic buckets! Well maybe this could go on the positive side too? Four things to measure. That's not all that bad. Kind of like making biscuits from scratch vs. Bisquick. You still need to measure out something. Doing it three times more is not that bad. Cost. It could be a little more expensive. I was using Redsea Coral Pro at about $0.43/gal ( I got it on sale for $0.36/gal). ESV is about the same as RS-CP when RS-CP is not on sale.