I am running about 2600gph in my 55g tank, I have 1- K4, 1- K3, 200gph from my canister, and 400gph from my sump return pump. The K3 and K4 are on a wavemaker and alternate every hour with about 15 minutes of overlap and then they stop from 11:00pm - 8:00am every day.
Forgot to answer your question, yes you can have too much flow but it depends on what you are keeping. Most fish and SPS coral can handle just about all the flow you can provide turnover rates of up to 60x are not uncommon in SPS tanks. There are several soft corals that don't do well in extremely high flow areas. LPS can handle pretty high flow rates too, the key with LPS and softies is not to direct a powerhead directly at them so that it whips the polyps around if you can do that then the overall flow rate of the tank is not really that revelent.