well i have 2 power filter units i am looking at getting. i need your guys opinion on them. the first one is a emporer 400 and the second one is a penguin 350. i know the emporer is more money but do i need to spend the extra. i know the it is the better. the unit will be in a 55 gallon tank replacing a aqueon 55 gallon filter. i also have a 80 gallon sponge filter. please help and give me some ideas. i do not want a aqua clear filter either