Will excessively aerating and circulation change the PH?

It can be caused by the composition of the airstone, especially the cheap blue ones. They are made from a mixture that is highly alkaline, and this can lead to making your pH go weird. Heat, air pumps "running hotter" and/or having the reservoir inside or outside of your tent, can in no way possible alter the chemical composition of your nutrient solution. Try making a circle of irrigation tube and piercing it in many places and attach your air hose to it, to make your own aerator and this will hopefully solve your pH problem. If you have no alternative to your airstone, try soaking it for a few days, changing the water very often, 5-6 times a day, to try and leach some of the "alkalinity" out of it before using it again. Otherwise, if you have a few connectors that fit the air hose, make up a multi tubed outlet that you can fit at the end of the main air line and weigh it down so it sits on the bottom of your reservoir and this will keep your solution well mixed. Hope this helps,.... Organoman.