Sumatran Water Monitor Growth

[Timmy87]

So I have had my water monitor for about 3-4 months. It has grown some. My friend bought his around the same time and they were both identical in size but since then his has grown alot bigger. there is probably a 3-4 inch difference. And I was wondering if I have stunt his growth. Is it possible to stunt a water monitors growth? I do have him in a tank that is 2.5 times his length. it eats like crazy. feed him about 4-5 pinkies every 3-4 days. My temp under the basking spot was about 95 degrees and I recently put in a flood light and its about 120ish now. i just barely bought a calcium spray for its food too to see if that helps him grow. Any feedback/advice would help.