You know... I've never lost any fish for not drip acclimating them to my tank. And as for a quarantine tank, I don't have the space or desire to have one. I expect that if I buy fish from a reputable source that they will be healthy. That's just a risk I choose to take with my tank. I'm not exactly sure why you decided to post this message but your input was unwanted and not requested.
You knock drip acclimation. So you went ahead & just added fish without quarantine. What did you expect. They had a disease & they wiped out your healthy batch. Your first batch should have been quarantined for 30 days as well. Drip acclimation is important especially if there is a TDS difference of more than 40 TDS. Otherwise the fish can die of ossmotic shock. The cells can swell & explode. It is the # 1 reason fish die when first introduced into aquariums. Drip acclimation over several hours can actually relieve stress on fish.