Your 53 should be fine, in fact it might be a little warm. Remember, the optimal temp refers to the temp of the fermenting wort which will usually be a few degrees warmer than the ambient air temp. I have 2 lagers going right now and have a water jacket over each to maintain temp. The wort has constantly been 2-3 degrees higher than the water temp. If you do ever need the heating pad, I have used the ones you buy at the pet store to put on the bottom of a reptile tank.