https://www.enasco.com/product/C14386N
here is what i use in the tub to keep the water warm. it has lasted for years.
Wish I could find one of these in about 60 to 100 watt. I use a 5 gallon bucket with chicken nipples on it.
I would think 250 watts would melt the bucket if it touched the side or bottom.
Wonder if I could run it on 24 volts. That would make it about 50 watts? P=IxE