the emperior 400 is the model above the Penguin from the same company. they are pretty much identical except for the following.
EMP 400gph motor VS 350 on the penguin
EMP spray bars to drive the biowheel and prevent te filter from backing up. Peng biowheel is spun passivly.
Emp larger filter media cartrages and Media box.
Emp is the better filter. there is no question. You can get them pretty cheap if you have a petsmart in your area. Cause you can print the price online and go to the store and buy it for that much. onine price is about 40 bucks.
If they try and give you some BS about shipping. Let them know that shipping costs are not paid to petsmart but to the shipper so the diference in price due to shipping is irrelivant. As well it is corperate policy to price match. And if a store tries to deny you.
Remind them of that. As well point out the sign next to the register about price matching.