With all of the talk of what is in our water lately........here is a site that explains the different kinds
http://www.exoticpetvet.net/general/water.html
I use GSE in my bottled water. I don't use it all of the time. I get a gallon of water mix the GSE in it and when it is gone, then I go thru another gallons without it and so on. Here is the site that I ordered it from. It will last you for a very long time.
http://www.pureliquidgold.com/