i have a 180 with barebone bottom without anything for the dats to hide..it consist of aro, 2 Marble motoros, and 2 Blood parrots, my ITs are always not stable but when i shut the lights off they will be little bit more stable and the NGT is the same also.
in my 56 column tank it's also barebone with no place to hide but it's only a dat tank which consist of 4 2.5" - 3" ITs and a 12"IT with 1 x 4" NTT and a 5" NGT..