Nutrients in your hydroponic system need to be kept warm. If they're not then the cold is likely to slow your plant growth and make a significant difference to the health of your crops, the yield you might expect or, in the worst case scenario, dead plants! You can easily prevent this with the Newatt Pro Water Heaters and stop your nutrient solution from getting cold. The heaters have very efficient heating elements and have an unbreakable tube together with electronic control of the temperature you set. This guarantees completely safe running. If you need to be sure the heating is on there is a pilot light indicator. There is a temperature scale on the cap that's used to regulate the heating precisely and easily without having to take them out of the water.