We have a SAN fabric set up with two Brocade switches (4900 and 5100) and a couple CLARiiON (cx3-40 and cx4-480).  We have been running on two ISL's between the two switches.  I was looking over the SAN Health report and noticed that the fan out ration was 18.5/1, which from some research was high.  So I want to add more ISL's.

Is there a problem with adding a couple more ISL's on-line, without affecting production?

Thanks in advance.