With plastic Paterson Super System 4 tanks and a simple water bath I get excellent temperature control. In fact I tried without a bath once using a higher starting temperature and it works too but I feel better using the water bath so that is what I stick with. 39C/102F at the start works well for me, I just have to look at the stopwatch to make sure I don't do an unintentional push as 3:30 goes by fast...