It's a bit expensive for an acrylic box. But, I use something similar to that. I don't use it to acclimate the fish to the water though, I use it to acclimate the current fish to the new ones coming in. IME it's been very helping when adding similar looking fish. I had a mystery wrasse (which is a notorious bully) and was able to add 2 leopard wrasses to the tank by putting them in the box for two months and letting the mystery get used to them. It's also good for finicky fish, I was able to train my leopards onto frozen food while they were in there.