Yes...I have multiple FX filters running on my 125G goldfish aquarium. I see some of the most successful YT fishkeepers running multiple filters all the time. I think it can cause problems if you don't stagger the maintenance due to the biomedia or if you don't locate the intakes on the same side. It also gives you a backup if you have issues and prevents me from needing a wavemaker. It also improves the CO2 / Oxygen exchange. You would not believe how gunked up the impeller gets. It definitely needs to be cleaned. I will do a video on the impeller at some point. Thanks for the suggestion!!! I clean the bottom of the glass and top with a hand towel dipped in aquarium water and then dry the top with a dry towel. I suggest emailing Aqueon to inquire about how to repair the glass separation issue.