I recently broke the E string on my Ibanez 5 string bass and replaced it with a 100 guage one. The sound level is now very low, lower than both adjacent strings. I have tried lowering the bridge, but this has no effect. Any ideas?

Replace it with the same size as the original and the original type. The 100 sounds right for the E. Make sure it is the SAME type string as there are non magnetic for some guitars and if you have magnetic pickups the bronze types won't work. There are also round wound, flat wound and some are flattened on one side. You need to make sure the replacement is exact type. Take sample of old to show store clerk.