Hey, do yourself and your sav a favor and forget quite a bit that the person you bought it from said to you, its all misinformation. ("Oh, i have a buddy who does this or that" good sign they dont know what they're talking about)

Right off the bat, heres some stuff to work on. Heat, should have a minimum of 120°F basking (130 is better imo). Use flood lights for monitors. For substrate, they need deep sandy dirt, they burrow like crazy. For an enclosure, go as big as you possibly can, what he's in now is way too small (eventually he will need an 8x4x4 foot enclosure). For humidity, they need 60% aboveground, and 100% underground. (That will be a TON easier to maintain in a large enclosure.)

Please check out varanustalk.com and savannahmonitor.net they have the most up-to-date care and very experienced people with monitors.