I am about to make the jump and purchase a robot to assist with the pool cleaning. We have a 18x36 pool with an 8' deep end. There is a grotto, 2 benches, and a tanning ledge with steps. Are there any robots that will hit the benches, steps, and grotto? I understand that the tanning ledge may be too shallow for a robot but I am really hoping one will get into that grotto as it is a bugger to clean from outside of the pool.