I will never add fish without quarantine again. I got neon tetras and added them without quarantine and my whole tank came down with columnaris. One of the tetras had a tiny spot on its lips, within a couple of days they were dropping like flies. I have a planted tank, so there are limitations on what kinds of treatments you can add. Now all new arrivals go into a 10 gallon bare bottom so I can treat them easily if they bring something home or if they pick something up from my tank that they aren't resistant to. I've recently been transferring a lot of shrimp from my breeder tank to my display, and I drip acclimate and then 15 minutes before I realease, I float the bag on top to allow temperature to equalize. For fish, I have always just scooped a little bit of water in at a time, but I am going to drip from now on. It is so easy. As far as water parameters go, it is best if you have similar water to where you are buying your fish. I usually ask what their readings are. They might do fine either way. I just know that when I was a kid, I could never buy fish from this one store because they would die within a couple of hours no mater how slowly I acclimated them. Looking back, I think the problem was differences in water parameters. The stores fish always looked healthy and I always had success at other shops. There are tons of resources out there, lots of opinions, and different methods. Best of luck!