The worst ta that I have seen was about -200. That means that, just to get to zero, I had to raise the ta by 200. If it turns red immediately, the ta is zero, or even less than zero. Therefore, yes, it can take quite a bit of bicarb or ph increaser to get a reading on ta and ph. It took over 100 lbs of bicarb just to get a good ta.
Do you have the T100 or k-2006?