I have a Koralia 4 and now am using it with a wave maker. The main problem I had was during start-up the Koralia rattles until the impeller catches. I emailed Koralia about how to fix the problem and they told me to get a bushing to put at the end of the impeller. I tried to find something that would work and didn't really find anything. So I used a small wall anchor, seems to have done the trick. No more rattle at start-up. The tech guy I spoke to said Hydor is working on a wave maker made for the koralia that will make them variable speed never completely shutting off, that will be nice, sounds similar to maybe a Tunze.



