I also have a 110 gal aquarium inside with crystal clear water, that I keep 4 goldfish in along with some white cloud minnows.
Well I've always notice that the goldfish outside had better color and grew bigger, so every summer I would put my inside fish outside for a few months and then move them back inside, as this would in my opinon help them.
Well after finding this site it has confirmed my thoughts on this. Hey I was doing good all along

Thanks Dale