Heat cable in exoterras

[forteh]

Need some info on heat cables if you will

Considering using them to provide background heat for my OHs crestie tanks, the ambient room temperature at the moment is about 68*F and it will get colder during the winter. Currently got heat mats but as they only provide a hotspot and dont affect ambient its pretty pointless for the cresties. Am I correct in thinking the heat cable will raise the ambient in the tank? Also does it give off a constant heat all the way along its length?

We have 5 45x45x60 tanks in a row and would like to run a single 7m heat cable to heat them all, controlled by a pulse stat. I have 2 plans of attack: -

Run the cable through the top entries, in a loop on the back wall and then onto the next tank.

or

Run the cable along the back wall of the shelf theyre on and put a loop out underneath each tank with the cable clipped down to the shelf itself.

I have a feeling that we will need to run the cable into the tanks itself to really be effective, I dont think running it in the airspace below the tanks is going to really raise the ambient through the glass. Was going to locate the stat probe in one of the tanks (probably the middle one of the 5).

If anyone has any thoughts then it would be much appreciated