Hi, Miss Bad Wolf, and welcome!
The email I got from Petco (I'm on their email list) said that 75 gallon tanks are now included in the $1 per gallon sale ("at select stores, while supplies last"), even though I couldn't find an online store flyer from any Petco I checked (across the U.S.) that stated it included the 75's, so you may want to consider a 75 as opposed to a 55 and see if your Petco will honor that. Heck, it's only six more inches further into the room, but it's 50% more landscape! That 50% can mak a big difference in 'scaping possibilities! I have plenty of 55 and smaller tanks, but no 75, so I'm gonna hit up my (semi) local Petco and see if I can score a 75 gallon for $75 this month.
Olskule
Olskule