(Lermer) A little bit of color-shifting is normal. If extreme, perhaps your bulb is going bad. How old is it? I'd re-lamp about every 4 months if you want to use just the best part of the bulb life.

For your ballast, the best all-around bulb is probably a super-HPS such as Hortilux. That has just enough higher output over-all and more blue, to be better than MH even in the veg stage. So I wouldn't bother with a new MH bulb, it might be better (than HPS) for the first few days, but for that the t-5 HO fluorescent works fine.

There is a major problem with the Lumatek e-ballast. It can run only MH or HPS, both of which are obsolete. Rather, I recommend a Life Light digital ballast, that can run either PSMH (pulse-start metal halide) or CMH (ceramic metal halide).