Dunno the exact specs of the cfl, but very often ghey are designed to operate at significantly lower currents (so higher arc voltages), in order to cut some of the cathode fall losses off. So the F4T5 could well be significantly underdriven (the ballast is very close to a constant current source), so suffering from cathode sputtering.

Or it also possible there is nothing wrong with the setup, the observed blackening is just a condensed mercury. If this would be the case, the "blackening" should disappear once the lamp warms up completely (after about half a hour running) and appear back only when the lamp cools down (so few minutes after power down) or even only at the next stsrtup.

I used the ballast from a 5w cfl, and even in the difference of 1 watt and being run for only a few moments, my F4T5 got a noticeable end darkening. But when I run other size of fluorescent lamps on higher wattage ballasts, they don't care much. The filaments on a cfl are smaller than a T5, so why is this happening?

M47 is 1000 watt Metal Halide. Nothing to do with halogen. Metal halides need a specific ballast to work properly. Any ballast marked "1000 watt M47 Metal Halide lamp" will work. If the lamps are still new, and you are looking to get rid of them, I might be interested as long as the shipping doesen't end up being too pricy.

I am looking to get rid of them. I'm in Hampshire, UK. Where are you?

Hello, I don't know if they are self-ballasted. I know virtually nothing about floodlight bulbs.
However, the 2nd reply in this thread seems to go some way to answering your question.

Oh, yeah.  I remember reading a book of Abraham Lincoln misspelling the word soldier somewhere.

I have been reducing the amount of meat I eat. Mostly because the amount of good vegetarian choices have become more and more available over here in recent years.

There are towns in Illinois which totally butcher the name of their overseas counterparts, Cairo Illinois is one of those towns. One word I refuse to mispronounce by emphasizing the letter L is solder. There is a youtuber gaining in popularity that sells a sticker of a fish wearing a top hat and jacket while holding a soldering iron and it says "Colonel Lincoln the Soldering Salmon".

I may post some items here again...or not. I may also try eBay again...
Another beef is that other LG members think I should give stuff away... 

Just took video of tornado siren music in my area. The tornado warning was actually not for my area, but the tornado sirens went off in my area, five
times. For good reason... there was an apparent tornado touchdown not too far from me, near Lebanon Ohio, which is apparently still part of Warren County.
Two confirmed tornadoes touched down.
The storm literally fell apart on radar rather quickly after leaving that area. Not sure of any damage reports as of now, but I did see a brief new video
of a tornado on the ground in Lebanon, from a news station there that I'm not familiar with lol

Just spent 5 hours... attempting... to drill out a broken bolt in my rear strut mount of my sport car. Failed miserably.
I've tried right handed drill bits with penetrating oil, left handed drill bits with penetrating oil, several extractors
including the famous "Grabit" extractors. Everything failed, miserably. The Grabit extractor actually slipped out of the
drill.
Either the drill is very weak, or maybe I'm doing something wrong.
And yes, I reversed the drill for the extractors and the left handed drill bits.