What I had forgotten is I used several scrap pieces of Poret inside the AC 300. The heavily chorinated water with the 16 ounces of Amquel added di run through the filter and then I unlugged it still full of that water. That water sat in the filter for a long time before I found ut and rinsed it all. Neither the cube filter nor the scraps looked discolored. I have the cubefilter in the bathroon and it is still black almost 8 hours later.Since its pH is less than 1.0 (<1.0 pH), muriatic acid is over a million times more acidic than neutral water (7.0 pH). This is one of the reasons why diluting acid is so important. Straight muriatic acid is so aggressive it can easily burn through flesh, metal and concrete. Plastic and glass can contain it, however.