Go to the Tunze forum in ReefCentral. Ask Roger and see what he thinks. I know sometimes manufacturers will feed you information just to sell their product but Roger won't 'beat around the bush'. From what he has said in the past, in the long run, a wavebox does weaken the tank. On average they will weaken over ~ 20 years. Now the likely hood of anyone in this hobby keeping the same tank that long is pretty slim to none. But then again, you do have the occasional instances of a tank leaking.

I just use my theory of: at any given point in time, at any given location, with the right amount of force, you can destroy ANYTHING ;)

I would go with a stream kit w/ multicontroller. Very Very nice

Also, OceansMotions makes some nice products for a closed loop:

www.oceansmotions.com