The best purchase I've ever made in my humble year of fish keeping was a python hose that attaches to the sink. You open a valve for siphoning water out and straight into the sink, and close it to reverse the flow to put fresh water into the tank. It's hard to temp match, so I use a thermometer to measure the temp of the water coming from the sink, but it does aerate the water coming out so chlorine isn't a big problem because it evaporates (I use water conditioner too, just in case). For big tanks like my 55 gal
, I can't imagine hauling buckets!