Here is how I keep my water table from freezing.
It’s a 12v DC heater pad for a RV holding tank. It turns on at 45 degrees and off at 65 degrees. I’m using a 6 amp 12v DC power supply and a 5 amp inline fuse. Perfect for shops that get below freezing. Not sure if it matters but I keep it unplugged when the table is in use.
Edit:
Stays plugged in all the time.
Where did you get it?
I tried a small magnetic mount that is made for oil pans. Left it on for days and it did nothing
Amazon. ASIN: B077VLB1KK
You will also need a 12v DC power supply. Minimum of 5 amps. I bought a 6 amp
From reading the description on Amazon it sounds like you have to wire it to a 12v DC power supply?
I was just looking at this heating pad on McMaster-Carr. It costs more but it plugs straight into the wall.
Heating Pad 35765k205
Correct. I mentioned that in my previous post. Oil pan heaters or block heaters are cheaper but they get up to 200 degrees. Also most of your 120v ac pads don’t have a internal thermostat.
Crap, sorry somehow I missed that post. Thanks for the info 
Would this be an acceptable power supply for the heater you mentioned?
[Power Supple](AspenTek Us Plug Dc 12v Power Supply Converter Adapter for Powering 12v Led Strip Light, Led Rigid Bar, Under Cabinet Lighting, Security Cameras, LCD Monitor, LCD TV, Ac 100-240v to Dc 12v 6A 72w https://www.amazon.com/dp/B00GU63ICU/ref=cm_sw_r_cp_apa_48eaCbAZ9VR0S)
Then something like this for the inline fuse?
[Inline Fuse](Lumision FAST Shipping ATO ATC Inline 16AWG Fuse Holder (Water Proof) + 5AMP FUSE https://www.amazon.com/dp/B00L6SAKK0/ref=cm_sw_r_cp_apa_F.eaCbA7ZW6QG)
Sorry if these are stupid questions but I dont have much experience at piecing together electrical components.
Same power supply I used and the inline fuse comes with the mat.
Awesome, thank you very much! You just made my project cheaper haha
No problem. Make sure you clean the bottom of the water table off with rubbing alcohol before you apply the heating pad.
Could you use something like a reptile heat mat so it would be 110v? Just adhere it to the bottom of the water table.
https://www.amazon.com/Zilla-Reptile-Terrarium-Heat-Large/dp/B002Z5O9IW
Not sure if 24 watts would be enough
Maybe an oil pan heater on a timer? Seems like they come in a variety of powers.
Just trying to find a plug and play solution for the less tech savvy guys that don’t wanna deal with a power supply.
Hows this working out for you? 5 years of sticking my hand in freezing cold water is getting OLD
Working really well! Everytime I have checked the water it’s been between 50 and 55. Right now outside temps are in the 30s.
The only issue, which I’m not sure if it’s just the dry air, is that the water seems to evaporate faster.
Could you mix the water with a bit of anti freeze or would the fumes be hazardous?
Standard antifreeze is bad. Really noxious and poisonous to breath its fumes.
RV Potable water antifreeze is okay.
Or just attach an RV water tank flat heater to it with a plug that turns it on at 35 and off at 45. You can get them on Amazon. There are a couple of threads here about that as a solution.
Ehh I have never heard of anyone doing that. Has to be rated for ultraviolet light too.
