Wow...My 3-part buffers right to 5.8-5.9 with ro water...Did you mess witht the calibiration on your pen? Using 3-part and calmag with rowater...You shouldn't have any problems like that, and NO...the temps don't affect ph, as far as I know.
I'll look in later. yellow is usually too low salts, but if you are following my recipe, then there is no way you are nute deficient or toxic...I can promise you that!