Flow rate alone means nothing...
How is it dissapated. If its all coming out of one outlet, I would say yes, its too much. If there are multiple of around 2-300 GPH, I would say no, its not too much.
I'm currently setting up a 30g (not my first tank, I've been keeping for over 10 yrs reef). I have a closed loop and return pump which are eheim 1260 and 1262. It's probably putting around 1200gph give or take a 100. Not too much, I have then going through 4 outlets and a spraybar under the rocks.
It all depends...
Also, what are you trying to keep?