Would someone be so kind as to post a picture of this elusive nipple please
As to yellow coloration, and nipples. My bulb is in a pendant, so it is vertical, and if what I think is the nipple, it would be sideways. My bulb is on a new M57 ballast, and burned pee yellow for a couple of days. Today it has burned with the correct color all day.
Here's a picture of my newly setup 20H nano. under the new 175W bulb.
Here's the same tank nine hours later. That is how the camera thinks it looks. It does not look that bad to me.
And here's the tank under 2X65W PC'c (one 10000K, the other actinic)
Not hard to guess which way I will be going until I get this bulb orientation cured.