This is one of the reasons my ex would always say it looked like Petco threw up in our house...only the aquarium section. I love to keep a variety of tanks on hand. Especially if someone is looking for the tank in our clubs when the sale ISNT going on. It's a real savings! I tell my LFS that's the one thing I'll always buy from the big box stores. Petsmarts round me don't have salt water fish or corals just Petco, however Petsmart has all but the livestock and for everyday stuff is cheaper. Isn't it usually PETCO that does $1 a gallon? Is Petsmart getting in on the sell them the tank cheap because they'll have to fill said tank. It's like offering $1 drugs for a week. Get me hooked on the hobby cheap. Watch them come buy everything for said aquarium! Probably works on more of your average freshwater beginner but for us reefers it's great for sumps, QTs, projects, and any other reason we can justify more tanks!
