Pezzep
Aquarium Advice Freak
Okay so I have this piece of sand stone (or I believe it's sandstone) and I did the vinegar test no fizz I soaked it in water for a week no PH change, but when I looked in the bottom of the metal container I was soaking it in there was this white foamy stuff that seemed to harden a little and the same stuff accumulated at the top of the metal bucket on the screws that held the handles. (See photos) what is this stuff and will it be safe to use the rock? Was there maybe left over vinegar on the rock mixing with the water and reacting to the metal/rock over the week period?