I've been running at 50+ ppm for several months now, with no noticeable effects. I'd guess what really hit you was the rate of change (e.g. if the CO2 levels jumped that high over a 1-2 day period) versus the actual ending levels. My opinion, anyways!
46g bf, XP3 w/ vertical spray bar, CO2 w/ SMS122 & diffuser,100% Flourite, 96w+55w cf AHS, AGA Member