Yes you get it at the grocery store, it's a 3% solution. You spot treat straight up.. no dilution. You basically shut off your filters and powerheads, whatever creates water movement. Take a syringe, draw up some H2O2, bring the syringe right up to the BBA and inject slowly. I believe it's safe to use up to 1.5 to 2ml per gallon. You'll see the BBA start fizzing with lots of tiny bubbles. After 15 minutes or so, you can turn your filter back on. You know it's working when the BBA turns red or pink the next day.