We realized that when you pour the diet coke into a different container than the one you have it in you cannot do it without making at least some fizz. The more fizz you make, the smaller the reaction is. This is why we had to measure how high the fizz went, and not how high the explosion went. We could not get it to explode because when we transferred the diet coke from the bigger container to the smaller container, all the fizz was released, which caused it not to explode. To have it explode, you have to keep it in the same container.
3 inches diet coke, 3 mentos (main formula) = 1 inch and 1\8 of fizz 4 inches diet coke, 3 mentos =1 inch and 1\8 of fizz 5 inches diet coke, 3 mentos =1 inch and 2\8 of fizz 3 inches diet coke, 4 mentos =1\2 an inch of fizz 3 inches diet coke, 5 mentos =1 inch and 1\2 of fizz