new hide affecting temp

I made a hide out of styrofoam and then covered it in grout and sealer, and when i put it inside my viv the temp drops down and wont reach up to the 96 degrees i set the thermostat at. im just confused by it.
First i was using a mini green plastic bowl upside down as his warm hide and the prob next to it, then i would take out the hide and put in the new one i made without moving the probe from that spot. After i put in the new hide the temp drops down and wont go past 91.2. Should i move the prob or do you think the hide is absorbing the heat or something? im just lost on why this is happening.

Styrofoam is an insulator and doesn't conduct heat. Grout is a semi-cement type compound, high moisture content do doesn't transfer heat well and then you sealed out all, basically wrapped it in a big shell taking away any best transference possibilities the felt might have had.

As nice looking and fun as it can be making these tank decor usually they'll require you to upgrade your uth and decrease substrait. Make sure the decor is directly over the uth and the probe should be in the hide where the leo will be sitting, that is the most important temp.

Hope that helps.

ok ill just stick with my first hide.
and i remember you telling me to bump up my temp to about 96, should it be 96 inside the hide or outside next to it? i have my probe right outside the hide and it gets up to 96 then the thermostat shuts off and kicks back on about 93. so im sure it gets warmer than 96 inside the hide.

You want to monitor the hottest spot where your leo is hiding. An enclosed space is bound to hold in heat since heat rises it'll be warmer in the hide.

so it would be best to put the temp prob inside his warm hide then?

Yes that's right your heatmat probe and the thermometer probe side by side on top of the substrate inside the warm hide.

my thermometer and thermostat probe are the same read outs. so i just put my thermostat one inside the hide and left the other outside next to it. and so far im getting a 1.5 to 2 degrees more inside the hide than outside.