How much is too much?

I have a 75 gallon and was wondering how much light would be too much. I have found fixtures that are 700w and I have found other fixtures with less. What is the point that is the point to stop

 

it isnt too much. just theres extra factors with higher wattage lights that are the question. heat and electrical costs are 2 of them. prob wouldnt need 700 , could get away with 400 and stil lkeep whatever youy wanted.

 

gonna depend on what inhabitants you want to keep, 700w on a 72bow will let you keep just about anything you want, but if your doing fish only or softies then it will be a bit stronger than necessary

 

well i want to keep up to millepora maybe even acropora

 

i have a 75 gallon tank with 692 watts, 10000 k and actinics powered by hamilton lighting. my mushrooms have adjusted to it, LPS are kept lower and softies are fine. The acro grows a cm every month or two so I guess I am saying 700 isnt bad, now 1000 watts may be high but I am still willing to give that a try.