So, I picked up an Eheim 2229 used out of curiosity. I have had a lot of canisters over the years and was curious if this could help me avoid setting up a new sump for a 55. The filter seems obnoxiously loud when filling at the end of the drain cycle. When it is running after filling and through the drain it is fine, but when is starts to refill it makes a really annoying buzzing sound. It seems to be that the impeller is pushing around some air. It is similar to when a normal canister needs to purge remaining air in the canister. I have no experience with this type of filter, but have watched some YouTube videos and don't hear the same kind of sound (almost none at all actually). Any help on this topic or comments from any of you that have a similar model would be greatly appreciated. I may upload a YouTube video tomorrow so everyone can see/hear what I'm talking about. I set it up in the garage to clean it out, check for leaks, etc. as it is a used filter. I don't want to bring it in and set it up if it is going to remain that loud.