i had an octo and i never did a super water change after an inking, thats like a total myth...sure it looks gross all black, but teh filter cleans it up in a few mins plus they dont ink that often, my inked like 10 times in 5 months! all my fault for walking to fast to the tank or being too loud. but yes, subdued lighting is good, but mine began to come out in daylight all the time!
just my experience.
Jon