Good evening Dkoh,
I like Andi’s method, at the end of the day it all depends on you in order to determine “when to remove”. But its normal to have a day when you have a spike down and then up. As long as the EA’s individually haven’t broken your trading criteria then there’s no need to worry/remove them. Fluctuations in the market happen, its Dynamic. If your back testing and forward testing are in alignment give them time to work.