Well, first thing that came to mind when reading this was that 70 gallons is going to be way to small for an adult colombian tegu. My 30 inch female is in a cage 6.5' x 2.5' x 2.5 and she uses every single inch of it.

Here's a pic so you can have an idea of how I have been keeping and her cage furnishings.

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0.1 Tupinambis teguixin
0.1 Tupinambis merinae
1.2 Thamnophis sirtalis pickeringii
1.1 Thamnophis sirtalis concinnus
0.1 Lamprophis fuliginosus
1.0 Heterodon nascius
4.0.4 Elgaria multicarinata
1.0 python regius
1.2.5 Eublepharis macularis
0.0.1 Phyllomedusa sauvagii
0.0.1 Rhacodactylus ciliatus
0.1 Sternotherus odoratus