Jack's Magic Blue Stuff

Anyone have any idea on what this Blue stuff is? Is there a "generic" chemical that can do what it does? (Is it just a metal sequesterer?)

I used it in combination with some acid to remove pervasive stains on my gunnite pool, and it worked well. However, I'm supposed to now maintain with it, which will be a pricey way to go for an entire season.

I will state that the method prescribed by the Jack's Magic people was mostly effective at ridding my pool of the grayish stain when no local pool guys could figure it out, so I am willing to use their product for a while (to repay my debt for their help!)

E

it is a sequestering agent. If you had problems with staining, you do need to keep a sequestering agent in your water, so you do need to use it for maintenance too. All sequestering agents are pricey - I don't know of anything else besides a sequestering agent you can use. So if you choose to use Jack's Magic, you aren't spending any more than you have to.