I have these same horizontal nipples that I put in a 6 gallon bucket http://www.amazon.com/Horizontal-Side-Mount-Poultry-Nipples/dp/B00JXUAD0K
They are great and there is no big puddle under the waterer like there was with the vertical ones. Also my vertical ones froze no matter how hot the water was it seemed.
I bought and tried this 150-watt heater which is supposed to be thermostatically controlled. However, It is keeping the water so hot it is uncomfortable to even hold my hand in.http://www.amazon.com/gp/product/B0002DHBDY?keywords=farm%20innovators%20de-icer&qid=1452203877&ref_=sr_1_1&sr=8-1
Two years ago I used a cheapo 50-watt fish tank heater in an open 3 gallon bucket for my ducks outside all winter and it seemed to work just great, so I am thinking I may do that again.
Though I am curious if the bird bath heater in the link in the previous post works any better than the one I tried though it is 250-watts and the one I tried was only 150-watts. How does it work for you Loc20chick?