Actually the water temp should be around 80 degrees or so to provide for a proper rooting temps. and also changing the water weekly should prevent root rot. but you do have to be careful about bacteria buildup and root rot. any cloning gel used? ive been shown that striping the green away on the bottom of the stems works for the fastest cloning. If you have a humidier around(or a friends /thrift store) consider that your clones will want as high of a humidity as possible (or mist frequently) With as minimal light as possible.