I run a deepwater culture setup. I use a 75watt small air pump to run air to 3 different rubbermaid 18gallon tubs. I keep them about 2/3 or 12 gallons full. My temps are great during light. But during night time my room gets around 60 degrees, but the water temp drops to 55 or so. I know this is way too cold. Soon as the weather breaks i won't have to worry, but there is atleast another week or 3 with possible low night temps. What are my ways to keep the water warm. I flush my water every 7-10 days. I would like to keep my temps around 68-70 degrees. When i ran my lights 20/4 the temps stayed fine. i tried a small heater but it didn't do much. I keep very good tabs on my ph 5.8-6.2 and my TDS either 450 or 750. I've only started to have issues since the drop in temps. WOULD LOW TEMPS CUZ NUT LOCK OUT? the top leaves on my plants have a glossy look to them with brown in the middle.