Well, it is quite possible that they are actually formulating their own salt since they do go through a lot of water... but probably 99% chance they aren't! If the 10k gallons every 3 days is accurate, then they go through around $1.9M in salt per year (estimating using the cost of Reef Crystals at $25/5gal wholesale... which you know is really about double what a "big bulk user" would actually pay)...plus, they are actually formulating well below 1.026 SG... so realistically they get more mileage than 160g from a 5g bucket...they probably spend about half that $1.9M on salt per year). Now i don't know how much it would cost to manufacture your own salt mix... but I bet after research/development, infrastructure, etc... your looking st a minimum $200M investment. So even at the high side of what they spend per year on salt, it would take them 100+yrs to break even on their initial investment... which doesn't include yearly upkeep, personnel costs, repairs, etc...
So, it makes more sense for them to go to Reef Crystals (or any salt producer) and say..."hey, we want to sell our own name brand of salt... how much would you charge us to change one parameter in your salt and package it with our name?" Way, way less than having to do all the work themselves!
But in reality, what is probably actually happening in order to even more financially benefit Live Aquaria: "Hey Reef Crystals... we are your biggest end user of your product now and paying $2/lb (just an example amt to show how this type of business deal works) for your salt in our facility...we would like to open up an entire new product line for you to increase your sales and increase your salt production to build your business bigger. We will sell your salt under our name, which is highly recognized and trusted in the industry... you'll have exclusive rights, and we will do all your advertising...but, we want to now get our salt from you for our business for now only $1/lb"... (of course the formulation will be slightly different).... This is a win-win for both company's... Reef Crystals just increased their sales and production while Live Aquaria just saved $1M off their expenses each year, plus making a little off each bag of salt sold.... and Live Aquaria didn't habe to put a dime into research/development, personnel, infrastructure, or maintenance upkeep.
Wal-Mart sells 100M+ bottles of Wal-Mart brand ketchup per year... you don't think they actually produce that themselves? Of course not, it's Heinz or Hunt's ketchup with a slight difference and repackaged under Wal-Mart's name, lol.