google where you live. find out your elevation.
for every 1000 feet (300m) above sea level you are. it is a 3.5% loss in vacuum.
I am 2200 feet... 7+% loss. I can only get 93% vacuum.
29.9 x .93 = 27.8 my vacuum gauge seems to get around 27.5... so yeah. thats about my max.
26.7 means you re at 3000 feet elevation/1000m. no its not bad.
yes, warm water does sometimes make it darker. also, older material does too. as well as if the plant is a sativa or an indica. fresh material run with low temps produces something like this ive found: