You have quoted someone who is saying exactly what I am saying and counters your claim that 10x the volume of the tank needs to go to the sump whether it's needed or not.

"as long as you understand that this does not mean that you need to move 1000 gallons of water in and out of your aquarium" :question:

I simply quoted where you suggested that 10x was the magic number, not one of these quotes was out of context, the very fact that you disagree with me confirms the fact that you subcribe to higher than lower flow.

I will be the first to admit I enjoy playing the devils advocate. A debate or discussion doesn't have to be an argument. As long as you present your position with some substance you can't possibly be wrong, just different. There's also no reason why you have to follow my advice even if it is valid. I've used oversized, less efficient equipment just because it works out that way sometimes.

There are many contradictions in the reef hobby. I've run skimmerless tanks, tanks with no water changes, closed loop (pressurized) filtration systems, and experiments with every method that warranted the effort. Some work better than others, but they all work. I've done more than a few 180's, but I always admit it when I do it. I'm willing to take or at least consider advice from the bottom or top of the hobby.

You have the right to disregard information, but you can't dispute it with hollow claims for 50 posts then try to back peddle that you never said any of it.

I'm sure this thread has been interesting reading and a great soap opera for all that are following. Three people in the aquarium trade having a heated argument about a simple subject. Everyone is going to think it was staged :)

I think this particular horse is sufficiently flogged. If someone wants to discuss the merits of water changes in a new thread, I'm there. I'll even take "against" :)

How about propeller pumps like Ecotech Vortechs or Tunze stream pumps? They address most of the cons of powerheads and consume significantly less power than a closed loop.

I would rather discuss the merits of not having teeth in an overflow box:)

This would make a great discussion.

Teeth not good? All the aquariums you buy with built in overflows that I have seen,have slots.

Yes they do.. why?

Because you imply that teeth are not good.
So I am wondering why are they not?

Teeth reduce the surface area by 50%, so a 12" overflow is really a 6" overflow. As water passes the teeth the surface tension is broken so you don't skim a quick, thin layer from the surface, but rather more water is drawn from below the surface.

Overflows that have a return line or other flow interfere with the surface tension (flow directed near, or away from the overflow) near the overflow cause it to draw water from lower down. You can do a flake food test on some overflows and see water (& flakes) pulled into the overflow box from straight down. Return lines from the sump should be located at the surface at one end with the overflow box in the opposing end or corner (depending on aesthetics). Centre overflow boxes are less efficient and promote dead spots. Water should flow straight across the surface mixing with old water and flow directly into the overflow box taking with it anything on the surface. This system discourages back siphoning with the sump return and provides superior surface swirl and subsequent ripples if you have metal halide lighting.

Tanks typically come with teeth because aquarium manufacturers don't like change. A single slot is cheaper, stronger and easier to build, but tank manufacturers are slow to change. Most of them still use wet/dry filters oversized drains (allowing air and flushing issues) and one pump systems. In the case of a coast to coast style overflow, teeth make even less sense because the water depth at the edge isn't deep enough to attract fish to swim over it.