pythium wilt/root rot. Anything over 72 degrees in the rez is just asking for future problems as bacteria will form. If you use additives such as h2o2 (amazing stuff i use the 35%) you do bring down the chances of nasty crap building up enormously. Ive heard good thing bout cannazyme or just a good enzyme additive but i don't really screw with that i rather just use h202 and make sure everything dead

. Happy growing.