I just bought these (2) Kroalia 4s from Don Duncan (beautiful tanks!) intending to use them as a replacement for (2) Koralia 1s that I have now. I didnt research these well enough, and
Koralia says these were not designed to be used with a wavemaker. The problem they have is when the Koralia starts up, the impeller literally tries to jump out of the socket they are in, and it makes a rattling noise until the impeller is fully running. These pumps really do make great flow in my 90G, but I dont want to mess with having to slip airline on the shaft to keep the impellers from jumping at startup. I've cleaned these 2 up and they run great when they are on. I'll take what I paid for them, 30 bucks cash each (firm). I'm in Gtown, but I work in RR at dell, so I can meet anyone in this area at my building, or in Gtown. I live up by the highschool.