I use a JBJ 13w "in tank" Submariner in my 125. I have no complaints. Plan on buying another one when I up to a 300, I dig the fact that they have the adjustable spray nozzle; I use it like a powerhead.
Used to have the "Green Killing Machine" still do in my growout; another in tank uv. I admit that even though it was a little cheap, It did do the job but the bulbs are expensive and sometimes hard to find.