Slight off-smell and (perhaps) orange mold on starter
I've been cultivating a new starter for about 2.5 months: white with a little rye as a yeast transporter (I've done this before with good results). Had no trouble getting it going. Added a little lemon juice at the beginning to offset leuconostoc infestation. Fed regularly. Tapered off the rye flour. Maintained good activity levels for a while, with rapid doubling. Waited for the 'juvenile starter' acetone-generating tendency to die back. Starter stabilized and developed proper sour/yeasty smell with good activity. Began baking with it. No problems. Loaves delicious, etc. Baking about once a week and feeding daily. Keeping the starter around 80% hydration.
Then the cold weather hit and my kitchen started going through daily temperature convulsions as I fought with myself about whether to turn on the furnace for a couple weeks (temperatures down to around 62 degrees, then up to maybe 68 in the daytime). I could immediately see the slowdown in yeast activity, but I kept baking with the starter and aside from longer (much longer) rise-times, it seemed fine. I was actually quite happy for a while because temperatures were such that I could cold-retard on the counter at night, which seemed to work great: developing the flavor without allowing loaves to become overproofed.
Then something started going off with my starter. I kept feeding it daily (keeping it on the counter in covered container with some holes punched in it). And I wasn't surprised when it stopped doubling in a couple-three hours because the kitchen still gets cold at night (though I've turned on the furnace now, so it gets up to around 68 in the daytime). But I fed it yesterday ... it doubled eventually ... sorta/kinda ... but today, I opened up its container and now can smell a sort of 'off' scent ... still backed by the sour-beery-yeasty smell (which I find delicious) but ... not so delicious. A little bit like ... (sorry to use this word, here, but I know you're all clinically-certified bread professionals) ... vomitus. And there looked to be a very, very slight, almost imperceptible orange-ish sheen on the top.
Looking for advice. Seems to me the cooler temps have slowed the yeast and maybe allowed something other than lactobacillus into a niche. So I've applied some first aid -- spooned off the top layer, poured off half, slung in some white flour, a bit of rye (reinforce the yeast population?) and a little lemon juice to help create a more weirdness-resistant environment for a while (though you would think the lactobacillus would be doing that, no?) And now waiting to see what happens.
In general, my experience with these things is that they're hard to kill once they're stable, so I have hopes of the patient pulling through. Am I crazy?