problems with pvc rack? so frustrated

Hey guys so I just bought my rack it's a pvc rack an has the grooves for flexwatt I'm using a viral electronics ve300 and I can't get my tubs set properly everything I do there's a big fluctuation between top and bottom almost ten degrees tried different probe placement in a bin as a dummy bin still nothing right on the flexwatt still bad fluctuations where do I put this probe keep in mind the grooves and my bin has tiny little risers on each corner

Almost forgot for eg I'll get my bottom bin to 88 but my top bin will be like 95 please guys any help is appreciated

The probe should be touching the flexwatt. It should not be in a bin. Tape the probe directly to the flexwatt.

Another thought is room temperature, what is the ambient temperature of the room? The colder the room the more heat generated by the heat tape. The localized heat rises at the back of the rack making the top boxes hotter.

Third, thought. I presume you assembled the rack, so you installed the heat tape. If the heat tape has a natural temperature gradient to the (current) top end, uninstall it, and put it back in upside down to its current position.

It's weird cuz the other rack I built wasn't even close to as hard as this one but again it didn't have grooves an it's the same room

How many levels is it? When I was building ten level racks it is almost unavoidable to have around a 7-8 degree difference.

Only 5 tubs so it shouldn't be that much

I would expect maybe a 3-4 degree difference between top and bottom.

How are you measuring temps on your end? Heat gun?

Ir heat gun and a regular temp gun no beam but I'm also using a thermometer with probe i got it from wal mart on top bin and bottom bin

Are you seeing a consistent incremental change in temps between the different levels?

OK so I figured it.out I bought a dolly to take it off the floor now there's only a 4 degree difference from top to bottom