Stuff only works if you first raise your pH and you have the ability to vacuum to waste. If not, it will cause a huge mess in your filter. Oh, and it loads your water up with sulfates...not good if you have an SWG.
But don't expect to see any of that info in their fancy video.
I'm of the opinion that the least amount of chemicals is the best amount of chemicals. My dad and I kept our pool pristine back in the 60's and 70's with a simple test kit for TC combined with bottles of chlorine and a little bit of Muriatic Acid. We cleaned the DE filters on a regular basis and never needed a shock treatment once.