The tank is 30x20x11 , It has two filters running on it right now one is a typical filter that it came with, the other is a carbon filter that can handle up to a 55 gal
. It also has a powerhead, I don't know the actual filter names. The tank is 6 months old or so.
We've never had any water problems, all our "spikes" in levels outside of normal cycles were due to moving all the live rock and mixing up the sand when we had to get rid of the mean yellow and black chromis we had, they beat up the rest of the fish and killed our cleaner shrimp