I'm going to go out on a limb as why lower quality water would raise life expectancy of goniopora. IMO nutrient rich tanks tend to have higher planktonic concentrations, providing higher natural rotifer concentrations in tank, plankton live on the nutrients, rotifers consume plankton, both of which the goniopora consumes. super clean overskimmed water doesnt leave the available food for constant feeding, I think the goniopora needs a steady constant diet, one spot feeding even once a day cant fully compensate for. this is just another untested, and unsubstantiated theory from the brain of a madman (me).