you can buy a salt mix and make your own as many of us do , it works out to about 14cents a gal , compared to premix 99cents a gal at pet store ,
How are you doing it for .14 per gallon???
are you including the cost of the tapwater, RO/DI filters and waste water from the RO/DI? Even when buying the salt in bulk, it is still around .20-.25 per gallon just for the salt mix.
(200 gallon box average price of $50 divided by 200 = .25 cents per gallon) Buckets are even more expensive.
I think your figures may need adjustment.
For me I have to buy RO/DI water at .25 a gallon cause my tap has copper and nitrate and then salt mix
(50 gallon bag is about .37 per gallon) and conditioner. So at least .62 per gallon mixing my own.
It works out to being more expensive to mix my own than buying ocean water from the lfs at .45 a gallon at one and .50 a gallon at the other I use.
Plus I figure in my time as well.
But I live in So. Cal and the company that provides the water is only miles off the coast, so shipping really doesn't add much to the cost for the stores.
There are stores around here who sell it for $1 or even as much $2 a gallon, but those stores are for people with more money than brains.
I can imagine it would be more in Co. or other inland areas.