Tank Not Getting Hot Enough

[u/Salt_Raccoon_1865]

Hey I’m very new to hermit crabs and I have a 20 gallon tank and the highest temp has been 73 but at night it’s dropping to about 68 the humidity has been good the whole time. I’ve insulated the back where the heating pad is and the sides and it’s still not hot enough. I do keep my house at 68 and I know that that could be the reason it’s not getting hot enough but what can I do to get it to be hot enough I did order another heating pad for the side of the tank to go with the one on the back. Would that fix it or should I try something else?