Hi Darran,
Did you get the one from ebay? i got mine from ebay but not that particular 1 mine came with moulded 3 pin plug
Do you use 1 or 2? - i use 2 as my set up is 2 500 ltr tanks, so 1 in each
What size tank to you have? - 2 x 500 ltrs
What temp does it heat the water to? - does depend on outside temp and how long you have them on but basically if i run them them from midnight to 7.30 am on a night of around 2 deg C water in the tank reads 48 deg C
Sorry for all the questions!
Andy
Yes it's like a big rad - nothing freezes ( well so far ) so has double benefits