I noticed a month or so ago that my Hydor koralia was always starting up in reverse after turning it off and back on. I just dealt with it for awhile even though it was quite annoying. So two weeks ago after I noticed the flow in my tank didn't seen right I took the Hydor apart and noticed the impeller magnet was starting to crack. Upon my search to order a new impeller I found out that on the older models there was a defect that was causing the impeller magnet to deteriorate over time or the front cover would break and either issue would cause the impeller to run in reverse. So before ordering a new impeller I happened to find out that Hydor would replace either of these parts for free as long as you provide model and batch number. I received 2 new impellers today completely free including shipping. After replacing the magnetic shaft it works like new. I have always been happy with my Hydor products and after seeing that they will stand behind their products even after the warranty is expired has earned my respect as a consumer. For those of you that have any of the older models listed here is the link to fill out the form to get your free replacement parts.