Has anyone used this de-icer?

We picked up this (http://www.fleetfarm.com/detail/allied-precision-bucket-utility-de-icer/0000000084936) this afternoon, and I'm hoping it'll work. I was wondering if any of you have used this particular de-icer or one similar? It will be de-icing about 3-5 gallons of water in a 15-gal plastic stock tank.

It seems like it could work perfectly for this set-up, but I do have a few things I'm worried might be a problem.

My three main concerns are

1) Burning? I wouldn't think this would get very hot - it's only supposed to keep the water from freezing, not get it hot - and since they said it works in a birdbath (which little birds get into), I'm hoping it'll be okay. It is also safe for use in plastic, so it must not get overly hot. Do you think I need to be careful about this?
2) the Teflon coating. Again, probably this is fine, but I remember a long time ago reading about how Teflon (perhaps in the air) is bad for small pet birds (the ones you keep in your house ). Do you think it's okay for it to be in the ducks' drinking water?
3) Too much heater for too little water? This de-icer is for up to 15 gallons - is 3 gallons too little water? Some birdbaths are quite shallow, so probably okay?

Thanks!

 

There is a little pamphlet in it - unfortunately I left the box in the coop and it's -4 degrees right now. I'll have to go grab it. Here is an online one, but it's not the exact same thing that's in the box, because I remember looking at it in the store.

http://www.alliedprecision.com/manuals/ag/DT250.pdf

Does the GFCI outlet help also with things like shorting out? (i.e. - if there was a crack in the cord and it was in danger of sparking and setting something on fire?). But, yes - I also saw that "if your animals are being shocked" warning...might be fine for a cow...but probably not for a duck!

Thanks, amiga! I'll try to get that pamphlet and read all the way through it.

 

Thanks for your help, Amiga! I ended up returning it because I wasn't sure how to deal with the mess of such a large, low container. So we're just going to keep using a 9-quart heated bucket, which has served the ducks fine so far. Thank you!