I only meant to enquire after his size; age was just my imprecise method. if he's an adult, that enclosure should be adequate, albeit a little on the large side to maintain proper husbandry for GTPs.
don't let chrondos fool you though: while they do just fine in enclosures ranging from a 24" cube to a quasi-terrestrial 4'x2'x2' cage, they will utilize the space you give them if their husbandry is accurate. you just might not see them do it. I've had more than a few insomnia-induced glimpses of my adult GTP exploring parts of his cage that I never thought he needed.
my last parting thought is that yours doesn't quite strike me as a sorong. the pattern is close, but they're not the only locality with a pigmented tail. I'm certainly no expert, nor do I think locality matters in the long run unless you're a breeder or wind up with a biak, but yours doesn't seem like a sorong.
how's his temperament?