This is all pseudo-scientific hype and has no basis in reality. I'd like you to do me a favor: Google "pentawater +randi". Don't worry, it's not an evil trick that pulls up something horrible, but it pulls up something very good.
You'll find a number of articles about, by or referencing James the Amazing Randi, founder, namesake and driving force behind the James Randi Educational Foundation. Pentawater, like so much other snake oil, relies on conflating a lot of scientific study with plain old balderdash. Randi is mean old coot who wants none of it. Reading the pentawater claims and hype should look familiar, like the tourmaline claims. Rex Grigg had an interesting essay on another woo woo aquarium device that is also worth reading. You can find it here: http://www.rexgrigg.com/debunked.htm
. Again, he outline's the anatomy of another quacky scam and again the ad copy looks familiar.
By the way, I know what product you're reading that off the back of or the marketing material for and it is is rather heartbreaking. It does do what it is intended to do, which is to lay down extra micronutrients and seed the substrate with soil bacteria, but the extra price for a semiprecious gemstone's perceived magical abilities really makes it a turn off. The same outfit makes a really cool canister filter that costs a boat load mostly because it incorporates a magical magnet from Germany that similarly affects the water molecules' structure and conditions it. Pure poppycock but again, depressing because of who makes it.
"You are much better off with no numbers than meaningless ones. The minute you believe numbers uncritically, that is, without understanding how they're calculated and how well they measure whatever they're supposed to measure, you will generate a breed of employee who will produce numbers and not results. Your data-processing system will then serve not to describe reality but to lie about it."
-Micheal S. Montalbano