Been burned by fixed volume thresholds for years

Back in the day I had a scanner with a hard volume number baked in, and it worked fine until it didn't. Every big cap tripped it all day long and the small stuff never showed up once. Took me longer than I'd like to admit to see the problem was mine, not the market's. That piece in the library here on volume surges with a spread guard says it plain - compare a symbol to its own last few minutes, not to some number you picked out of the air. The spread check is the part I never bothered with and probably should have. Stay humble.