fermenting temps

i am brewing a Saison and used wyeast 3711. I was trying to ferment at high temps with this yeast. I brought the fermenter to my second floor which is usually around 70 degress f. I was hoping to get it around 80 so I put a under tank reptile heater on the side of my better bottle. I cant really get in the carboy to check the temp but i put a sticky thermometer on the opposite side of the heater. It is only measuring around 72 degrees but that is through the better bottle. Do you think the temp inside is higher?

Temperature inside can be anywhere from 5-10F hotter than the label on the outside reads at fermentation peak. You can try wrapping a blanket or towel around it to keep more of the heat in as well.

Thanks, but I am a bit afraid to wrap anything else around it because of the plug in heater. Do u think it would be safe?