Another Heating Question

Hello, I have two racks, one rack with 41 qt tubs (with Herpstat1 thermostat and heat cable) and the other with 28 qt tubs (with Vivarium Electronic and 3" flexwatt heat tape but I should get the Herpstat1 tomorrow).

I'm curious, what is the difference in degrees?

On my 41 qt tub rack, I get about 6 degrees difference. I use paper towel as substrate and I put two layers of paper towel. Should I just use one?

With the 28 qt tub, I have it set on 98 degrees to get 91. That's 7 degrees difference. Normal?

What's the temperature in the room? I just got my first rack and my thermostat was about where your smaller rack was because the room wasn't warm. When I had my bearded dragon lights on during the day and the room temp was in the 80s I had to turn the thermostat down.

The room is at 72 degrees right now but it will go down to maybe 65, 60 overnight.

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Originally Posted by digizure

The room is at 72 degrees right now but it will go down to maybe 65, 60 overnight.

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I couldn't do it.. I'd freeze to death! I've gotten so use to living with reptiles that if my house drops below 74 at any time of the year I feel like I'm going to have frost bite! Lol

Had a space heater on in my room last night even though the house furnace is set to 74, and my sons dad comes in to wake me up and freaks out about how hot it is. I'm cuddled up under the covers feeling juuuuuussst fine!

I'm in San Diego so it doesn't get that cold here. :)

I'm a little frustrated because the temp for each tub isn't the same. Any ideas why that might be? I just want my pythons to get 91 degrees in the hot spot during the day and 82 degrees at night.

Where have you placed the probes for the thermostats? They should be taped directly on the heat source. For the rack with the flexwatt tape a probe directly on the heat tape in an area where the tub in that slot won't hit it. If its a pre made rack it should have grooves and or slots in the back going through to the inside back of one of the tub slots just for probe placement.

For the rack with the heat cable tape the probe directly to the cable.

Then you have to consider that there will be a difference between what you have it set at and what the hot spot inside that section of tub is. The heat is being diffused by the amount of material it has to travel through so you set the thermostat at whatever you need to set at to get the required readings inside the tub.

Those internal readings should also be taken with a probed thermometer or a temp gun in order to be sure you're getting accurate readings within a couple degrees.

I have the probe taped inside the tub, right over the heat tape. I don't think I should take the probe out of the tub because I want to know what the degree is inside the tub.

The rack is an open rack system with no sides but it is placed against the wall.

Another thing, I have the top rack at 88 degrees and the bottom rack at 82 degrees. How do I regulate this? Thanks.

You're going to have issues until you put the probe for the thermostat that controls the heat directly on the heat. You have to consider the fact that the plastic insulates and diffuses the heat. By the time it's hot enough for the probe (if it's inside the tub over the heat) to pick up the temperature that you want it it to be at, the thermostat is reading a much higher amount because that heat has had to travel through the plastic.

Then think about the many degrees of difference you're going to have as it cycles down and then back up because of that issue. Instead of the probe being able to keep the heat at one consistent temperature, it will constantly raise and lower the amount of power, or if it's an on/off thermostat it will be constantly be turning on and off with many degrees variance between because it has to pass through all that plastic..

Then it takes the plastic slightly longer to cool down even when the actual heat tape has cooled down a bit moreso, which means it will take longer to heat up again. Do you understand the issue here?

It's a dangerous issue, and a costly one considering the extra power being used to compensate for the heat being diffused through plastic before its probe picks up the proper temp and turns it off or cycles it down. This will also wear out your thermostat quicker..


I'm telling you, you need to put the thermostat probe DIRECTLY on the heat source. Then put a probe for a thermometer directly on the plastic inside the tub over the heat source. Set the thermostat to where it needs to be to maintain the internal hot spot that you require as being read by the thermometer probe inside the tub.

As for having no sides, you can easily insulate it to help regulate the temperature and help the thermostat function easier by putting those thin pink sheets of insulation on the sides. You can pick them up at any home depot type store. Have them cut to fit and just tape them on. You can paint them to match the rack first if you like.

X2

The tstat probe needs to be on the heat cable. They sell thermostats with a probe for pretty cheap at Walmart, just get one of those to monitor the temp in the tubs.

I am also in San Diego and it also sounds like you need a oil filled heater in that room... We're going into fall right now and it's just going to get colder. You need to insulate like stated above and have the space heater going to heat up the room.

The flexwatt in a rack is basically for creating a hot spot only, the oil filled heater will raise the ambient temps in the room and the rest of the tub.

I tried placing the probe on the cable and it got worse. I did some searching and found that Spyder Robotics does not recommend placing the probe on the cable because it heats up/cools down too fast. They suggested that I put the probe inside the tub. I was told two different things and tried them both, A) Place the probe on the bottom of the tub (inside) underneath the paper towel and B) Place the probe on the back wall inside the tub, about an inch above the bottom of the tub.

Both methods does not work too well for me.

This morning, I noticed my thermostat set on 82 and saw that it was pushing 100% power and used my heat gun and found various temp inside the hide, ranging from 91-105 degrees. WTF??? Is it possible that my thermostat is bad? Or maybe my probe is bad?

Then I'm not sure what to say about it. I use helix, herpstat, and ranco with flexwatt and I've never had that problem with so much of a variance. I only have a couple degree variance from bottom tub to top tub. I don't think I've ever heard of anyone having such a variance. Then again, not a lot of people use cable either. I honestly don't know what the issue is if the thermostat isn't keeping a steady temp even when the probe is directly on the heat source. That is very odd.

If you had to set the thermostat to say, 96 (with the probe directly on the cable) in order for the hot spot inside the tub to stay tight around 90, give or take a degree, that would be normal. Your problem is different and I can't figure it out.

I guess the probe could be bad or not plugged in all the way but if you adjust the setting down does the temp drop?

It might be staying wide open because the probe isn't on the cable. the heating element has to get pretty hot to get 82 degrees through the space under your tubs, and the tub itself not to mention substrate, and more air if you have it on the back wall. If it is on the back wall crank it down to like 78 and see if that helps or move the probe.

the probe really needs to be on the wire for a couple reasons.

1: Its reading right at the source. If its in the tub or, even worse, the back of the tub then the heat cable has to heat up way past what it needs to for the heat to penetrate through the tub and up to get to the probe to shut it off.

2: it's a lot less likely to be knocked off or accidentally disconnected if it's stationary.

The temp that the thermostat is reading is irrelevant if the temps are correct according to your temp gun. For example if the thermostat is saying that it's 60 degrees at the probe but it is the perfect temp in the tubs then your set. Just keep playing with it until it's where you want it and then see if the temps hold throughout the day for a couple days.