I have 4 animal plastics tanks. they range with weight. I would say generaly around 60-80 lbs. I recommend using an rhp as if you do not provide atleast a 1/4 inch of space for air flow the heat tape/ flex watt will over heat and have a chance to cause a fire. investment wise best investment I have ever made and their customer service is superior. ali is phenominal. I needed a tank by Friday so I orderd a t8 on Monday and she had it to me Thursday afternoon. that is customer service to the max.