What are you using for a fermentation chamber? If it is just an insulated enclosure the ice and the thermometer will work. If you want to use a freezer or fridge to ferment ales in the 60 degree F range, an SCT-1000 temperature controller, $20 from Amazon, works great. Allows you to maintain a constant temp using the existing cooling system and heat with a 60 watt ceramic heater. Used but relatively new 4 to 5 CF freezers and fridges can be purchased from $20 to $50. Just make sure you can close the door with the plastic bucket / carboy inside.