[coral reefer]

The refugium can be a very versatile and important addition to the symetrical balance of a reef tank especially! It houses a diverse population of bacteria, food sources such as pods, micro-invertebrates, macroalgae, small shrimp, snails, crabs, worms, fry and other microscopic organisms!
How you set it up and the size of the refugium is up to you...with benefits evident with any refugium set-up.
I don't like the bioball addition as they are good to a point until the balls get accumulated with detritus etc. causing the rise in nitrates-leading to but not limited to the growth of unwanted microalgae! Having to periodically clean these ball to rid the pollutants and detritus from accumulating on these balls is a pain in my opinion, when you can get better and a more natural result by implimenting live sand and rock to the refugium/sump!!!!!!!
This is just my opinion so take it for what its worth but, I have been doing this type of set-up for years while eliminating bioballs from my tanks overall function with great results!