A pretty poweful basic solution. My boss dumped about 20 ml of 29$ NH4OH into our 2000-gallon waste water tank, and it raised the pH by over a point. She also nearly knocked herself out, because the fumes are so bad that they cause your body to shut down the intake to your lungs. It smells like ultra-concentrated cat piss mixed with paint, and feels like a kick in the face, even if you're standing six feet away.