There are many factors regarding if a visit to the PW by a nem will crash your tank or not. Tank size, maturity, nem species, filtration system all play a major role. I’ve had my fair share of nems go into a PW, from small BTAs to a XL BW nem (that one still hurts ) and my tank always pulls through with little consequences (other than a bruised ego). The bigger your tank, the better your export methods, and the higher amount of bacteria or live rock you have should help you ride out any unfortunate incidents in your tank.