some time ago i built my own little heatbed:
First of all some facts about the heatbead. It is filled with regular filter sand. The first layer of sand is about 4cm (1.6 inch) then comes a layer of thin metal mesh together with the heating cable and on top of that again 3cm (1.2 inch) of sand. The temperature is controlled via a computer with a thermostat which measures the temperature in a depth of approximately 2cm (0.8 inch).
The temperature is hold at 22°C to 26°C depending on the outdoor temperature.
Till now i am very happy how everything works but i am wondering how often do you water the heatbead? At the moment i water it every 1-2 weeks with one liter. The surface is abotu 2 square meter. Do you think this is fine or would you water more/less?
Thanks for your opinions and experiences.