@Nbourre I fondly remember doing this lab in HS myself! The bubbles are not neutralizing the acid, the antacid tablet/powder is doing the neutralizing and the CO2 bubbles(and water) are the products.
So, the more bubbles the more effective the antacid was because it produced more CO2, meaning more acid was neutralized in the reaction.
@BE This is perfect. Thank you so much. I have passed the info along an dnow it's up to him to finish his report.