although I haven't used them a few people told me that the Koralias don't hold up well to the constant on and off....I've been using Maxijet1200s with the mods on a wavemaker for close to a year now no problems....cheap alternative to a MP or Tunze
that is the link to the thread where I asked about the same situation. It starts out talking about the RKL, but a little bit down it talks about the Koralias. I called the Hydor and they said that they completely redid their koralias and they are more powerful and are able to be used as wavemakers unlike the old ones. GOOD LUCK