Mainly it was money based my dad thought it was a good idea at the time. But as time went on dry rock just kept leeching and kept giving me problems.What is your definition of efficient? Is it time based? Money based? Energy based? I can show you 2 different tanks 1 lr and 1 dry. The dry rock was more efficient in cost, time spent maintaining and overall outcome is less time also. Those would not be good comparisons though as filtration, lighting, fish are all different there for a different outcome.