It's just not very well designed in my opinion. Tends to be noisy if pushed towards its capacity. I personally much prefer the larger, single units from either Modular Marine or EMS.
Edit - I see you found the synergy thread .....
I don't see how the modular marine design is any different?
Personally I think any overflow with teeth is a design flaw because it cuts the length of your effective overflow in half, thereby doubling the velocity of water but whatevs. That is the way it has been done in the past so that is the way it continues to be done.
A lot of thinking and planning to do now, I imported the Synergy ones so quite some money there just in shipping, I hate wasting money like that :mad: