I have had a refugium, a refugium and a sump (wet dry) and just a wet dry. Refugiums definately have their place if set up right, but IMO
I can run a system just as efficiently without the refugium as I can with one. There are 2 basic reasons to have a refugium. Macro aglae filtration and a breeding groud for pods
. In small tanks (tanks under 75 gallons) the refuguim can be useful because its relatively easy to get close to the same water volume in the fuge as in the tank. That is key to a successful fuge if macro algae filtration is the reason for the fuge in the first place. (this isnt as important in "haven" fuges) Larger tanks become much more of a challenge. Who has room for a 175gal tank and a 175 gallon fuge? (Besides BangGuy...900 gallon lagoon fuge in his basement.)
If your setting up a pod haven fuge, the key is to use a pump to return the water and not a power head. The impeller on a p/h will kill most of the pods
passing through it. If the pods
cant get back to the main tank..whats the point of the fuge in the first place.
I have an article on fuges that is very in depth if you would like to read it.