Rack tub temps vary between 85 and 95 on heat tape?

For my four level rack with heat tape, the hot spot of the top tub in certain spots are up to 95 while the hot spot of the very bottom tub is only about 84-86. The ones in the middle also vary (depending on the spot on the heat mat) between 85-90ish. If I lower the thermostat temp (which the probe is under the 2nd to top tub), the bottom tub temp goes way down to even 82, and I don't want that.

I got this rack made brand new with heat tape around the end of 2016.

Is it the heat tape going bad, or is it's just the way a rack works? Which would suck, because that's way more temp variation than I need. If I switched all the heat tape out for ultratherm UTH of the same size, would the temps consistency improve and would that be safe?

The heat tapes are all plugged into a single extension chord which is what is plugged into the thermostat. (a herpstat)

bumps if anyone might know. hopefully bumps are allowed

I have three tanks stacked in my set up, and I easy can scan a six degree difference in the winter from floor to ceiling. I have to keep a close eye on my top tanks, and obviously set the heat lower on the top ones. I know that probably doesn’t help with your problem, just trying to say I relate to what your saying. I remember back in the day hearing breeders having similar problems. Hopefully someone with rack experience can offer a work around or an outright solution. Good luck.

I noticed the same thing in my ARS racks, I actually have a separate heat controller for each level for my breeder female rack. But my hatchlings and growouts and males just have to deal with it, they all seem to be doing fine with the heat differences. My room is at 81F so no one is below that. I set my thermostat to 90F and put it on the middle level.

I've had this problem with two of my racks, mainly the ones wired from the top to the bottom. My theory is that the end of the heat tape takes longer to heat up than the beginning, and since heat rises anyway the top just gets more of it. The discrepancy is a lot less in my racks that are wired from the bottom to the top.

Not a whole lot you can do about it unless you take the rack apart. I have one girl who likes lower temps in the bottom of my breeder rack, and a kingsnake in the bottom of the smaller one. He doesn't mind being in the mid 80s at all.

Also check the tubs to make sure the bottoms aren't warped or bowed. You can try running the rack for a while with some heavy books in the tubs over the heat tape to simulate the weight of your snake and then take readings to see if there's less of a variation.

Dang, that sucks! Maybe I'll ditch the rack then... The bottom tub temps are so cold now that it even put one of my ball pythons off feed who has never missed a meal in his life before a couple weeks ago, so I decided it was an issue. I only put him in the bottom tub since he is the most foody out of all my snakes, but it didn't used to be this cold.

I was told about how the top tubs are warmer and bottom is colder, but this is way too large of a difference for just ball pythons I think. :S Maybe I'll sell the rack

BCR, I was actually measuring the heat tape by moving the tubs off and sticking the temp gun on different spots directly.

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Originally Posted by redshepherd

BCR, I was actually measuring the heat tape by moving the tubs off and sticking the temp gun on different spots directly.

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Oh you don't want to do that. Heat tape itself can have quite a bit of variation just like any other heating element such as a stovetop (sidebar, this is why higher-end pots & pans have copper bottoms, to help disperse heat evenly). Put the tubs into the rack, put down a piece of paper, and put a heavy book on the paper over the heat tape in each tub - the book will ensure there are no air gaps to mess with your readings. Let the rack run for a while and then measure the temps on top of the paper after you remove the book.

Quote:

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Originally Posted by bcr229

Oh you don't want to do that. Heat tape itself can have quite a bit of variation just like any other heating element such as a stovetop (sidebar, this is why higher-end pots & pans have copper bottoms, to help disperse heat evenly). Put the tubs into the rack, put down a piece of paper, and put a heavy book on the paper over the heat tape in each tub - the book will ensure there are no air gaps to mess with your readings. Let the rack run for a while and then measure the temps on top of the paper after you remove the book.

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Oh thanks, I didn't think of that! I'll try again and see. Is the paper for holding the temp longer after sliding out the tub, I guess?

Rather than ditch the rack why not just run single heat tape for each row or extra in cooler rows?

i don’t have a rack but when I was looking at them I’ve heard a few stories such as yours and most folks added another strip or a side strip because like the one user said the spread of heat carries greatly from one area to another

even in my 4x2 pvc I have a 23” by 12” heat tape and I see descrepencies and had to play with it and it was rather frustrating at first.