There was no snark intended, honestly. I didn't know that a 40 breeder was closer to 48 gallons, I've heard everything from 40 gallons standard to 45 gallons, but never heard up to 48 gallons, and always just assumed 45 was an outer measurement, not an inner measurement so that's why people think it's 45. I've also never bothered to run the math. I did also try to look up that Fluval tank and it's not listed on Fluval USA's website, so I did not know that it was an AIO, I assumed it wasn't. So then yes, the gap is much wider than I initially thought.The difference is that a 40 breeder is a 36x18 tank with an actual volume of about 48 gallons, and that fluval tank is an all in one with about 9 gallons in the rear chamber. Thanks for the snark, by the way. That's always helpful.