For my leopard gecko tank I use an under tank heater. Under tank heater will cause stress cracks if water is directly over the glass where the under tank heater is when the under tank heater is heated. I want help on how to clean with a under tank heater. This question may be dumb but I am a beginner about to get a leopard gecko and I don't to ruin my tank and I can't take the under tank heater off when it is in place.