I've recently learned that if fish have been shipped, and have been in the bags for several hours, you're better off *not* drip acclimating, because the ammonia they excrete while in the bag is largely less toxic because the excess CO2 in the shipping water lowers the pH. When you expose that tank water to the air, the CO2 off gasses, resulting in a pH jump up, which allows the ammonia to become toxic again, and quickly.
If you're still wanting to acclimate the fish, be sure to *immediately* add something to detoxify the water in order to offset the ammonia spike. The aforementioned Rachel O'Leary has a youtube video up about it, and she's not the only one.
I didn't *know* that until last week, so it's fresh in the mind still. I'm surprised I hadn't picked it up from someone on here earlier.
I mean, I know I had been gone for a few years as a result of some changes in work and mental health (the lack of ethics at my job was brutal to my mental health; I've since left that environment). It was all I could do to keep the stock I had in my 55 alive as long as I did, and I still have my BN, but everything else aged out, it seems. I took some time to watch some videos on Youtube, and saw three people that seem pretty knowledgeable say the same thing, and it sounds pretty logical if you understand the chemistry portion of it. I just knew enough to know that the shipping water is usually high in CO2 and ammonia.
There might be instances where it could be true, but the pH would have to get under 7 for that to happen (ammonia<->ammonium remember), so it was either very soft and neutral to begin with. I've worked in that industry and I measured the pH in bags and most farms, wholesalers and shops do not use these kind of conditions. Fish aren't fed before shipping overnight, bags are filled with oxygen not air, and coal is often added too. When normal stocking is observed for bags, it is not a concern.
pH not temperature is why you drip, I always do it and recommend everyone does it.