As the brew ferments it creates more heat inside the vessel. We use stick on thermometers (aquarium thermometer) to judge the fermentation temp, by lowering the ambient air you will bring the temp of the actual fermentation down to the temp range of the yeast. The temperature for the yeast is what you want to control. You can move the brew to a cooler area, or use what is called a swamp cooler to keep the vessel temp in the desired range. The hydrometer is the way to tell if you have reached FG, Refractometers are a good tool to have, if you use it from start to finish. But I still finish with the hydrometer. I have had brews bubble for 30 days if I press down on the bucket, bubbles are not a reliable guide to go by. If I were you I would simply wait 3 weeks to bottle and test once with the hydrometer and refractometer, record the readings for future reference, drink the sample and move on to the next LARGER batch. Cheers and enjoy; you can not rush the process.