Red Sea Root Therm 400 Root Heating Cable.

Substrate heating system for aquatic plants. 40-watts, 16.4-feet long, rated for up to 100 gallon aquarium. Aquatic Plants will display healthy growth if they are provided with "warm roots" - i.e. the temperature within the substance is slightly higher than that of the water above. This temperature differential between the substrate and the water induces a gentle water circulation, which both prevents the formulation of stagnant areas and the build up of undesirable by-products within the substrate while providing the roots with a constant supply of the nutrients necessary for optimum plant growth and vitality. Regular thermostat controlled aquarium water heaters, will keep the water above the substrate at a stable temperature however the temperature of the substrate and the plant's roots will always be slightly below the water temperature. Low power substrate warming, in addition to regular water heating is therefore the logical solution for maintaining a positive temperature differential between the substrate and the water, ensuring that the plants will have the "warm roots" they need. The RootTherm kit provides gentle warming suitable for planted aquarium set-ups without the need for a temperature controller. The RootTherm will work in conjunction with any regular aquarium heater-thermostat. Durable & safe 24v system.