I have an exo-terra 18'x18'x24' glass terrarium and a 100w infared bulb. First I had the light at the back left corner but it started melting the back ground. So then I used the clamp and hung it over the top middle but, then it started melting the plastic bar across the top. Would it be ok to have the light come down diagonaly through the glass or would I lose some heat because of it? If so what would be a good solution? Please help me.
It might lose some heat, but its better than ruining ur tank top. No matter where u put the 100w it is going to heat the plastic up too much, so ur glass idea might be your only choice. Try a uth and a lower watt bulb with something between the top and the light, if the through the glass doesnt work.
