I did my first 5 gal AG Pale Ale last weekend and went pretty good OG 1.050 what I expected. Now fermentation is happening I think really well, however I am concern about temp controller. I am using analog Johnson A19AAT-2 set on 65F, and comparing with a digital temp inside freezer ambien temp swing 68.5F to 63F. I know a differential could be the reason but also want make sure if having the probe attach to glass Carboy or just hang inside freezer make difference. What would you recommend?