Why would you replace your koralia? i have them and love them
Actually i'm going to re answer this question in depth.
A koralia 4 consumes 12w for a max of 1200gph. I won't compare the others as they can't be considered close based on gph.
A koralia has limited range of swivel direction.
Koralias have been having problems on seio controllers.
Koralias can not be cycled off and on on a wavemaker.
Koralias magnets aren't really powerfull enough for thick tanks.
Koralias are known for premature failure.
Now on to maxijets.
A maxijet 400 consumes 5w, a 600 7.5w, a 900 9.5w a 1200 15w
You can run 2 400's with the mod that consumes less than a single model 4 koralia. Typically less power consuption can lead to less heat in a display also.
with the mod there are numerous mounting abilities and a larger range of swivel movement for positioning
Maxijets have given many reefers reliable service for years and years.
Maxijets can be run on controllers and on wavemakers.
Maxijets have proven to be very reliable over the years.
You can buy optionally stronger magnets that actually fit properly for thicker glass tanks.
This goes for oceanflows or algae free's.