[scikit-learn] Any way to tune the parameters better than GridSearchCV?

Take random forest as example, if I give estimator from 10 to 10000(10, 100, 1000, 10000) into grid search. Based on the result, I found estimator=100 is the best, but I don't know lower or greater than 100 is better. How should I decide? brute force or any tools better than GridSearchCV? thx