We plumbed water to my 55 gal
by tapping into the cold water line under the kitchen sink and through the wall into the living room. It helped that the living room was still under construction of course and the walls were open.
We use a 1/4 line and tap like you would use for your icemaker/water to your refrigerator. It works pretty well and fills very slowly. when I do large water changes I have to bring in a few buckets of warm water to even out the temp difference but in your case that shouldnt be an issue since you are changing very slowly.
We want to do an auto top off and have even purchased a small float valve that will work with the 1/4 inch line but have not done anything qwith it yet.
I am very interested in following your thread!
Thanks for posting it!