If you have the old wet/dry systems, you will get more out of it when converted to a fuge. Its easier than you think. Take out the bio-balls, they help produce too many nitrates. Take out the filter pads also. Raise the pump half way up so it does not suck up sand and fill the wet dry with water as much as you safely can while off to determine the highest water level when off. Replace with a good sand bed of 4 inches if possible, find some macros to plant in your filter, get some good quality live sand, pods and a shop light on top lit 24/7 and you have the beginings of a well balanced tank system. pH swings will be gone, oxygen values will be at optimal levels all the time, your environment will be functioning as it should and your specimens will have better health and live longer. I recently converted this year to a fuge and I am sorry I didn't do it sooner.