So my bedroom and tank are in the basement, the only sink I have down here is a laundry sink and the hot and cold spouts are separate. My tank is a 55g and I use an aqueon water changer. The problem is now that fall is here the water is coming out colder and colder and it made my tank drop approx 6 degrees doing a 50% water change. I realize this is bad and has never happened before, the fish seem ok currently (there are two 4" Texas Cichlids and 6 x 2" silver dollars). The tank is temporary until I move after January, instead of doing 1 50% water change a week should I do like 3 20% ones to avoid such massive temperature swings? If not what are my other options to stop the water from getting so cold. Thanks in advance.