What is an over flow tank and why is it needed?

Question

looking to start a 55 gallon salt water fish tank

Answer 1

it is not needed,but nice to have.i would use a 30 gallon for that size tank, but another 55 would be awesome,too then you would have,more water volume.it's added expense.use cpr brand 300 gph flow.pvc it to a filter sock,in the sump,you decide to use.keep a sump skimmer in there, heaters,etc.add replacement water to the sump when needed.go on reefgeeks.com for more info.the possibilities are endless.you can put it in back of the show tank,or in the basement and have the water pumped back up to the main tank.i have a used good shape already plumbed cpr300gph overflow i'm not using as i got a larger one.i get the socks for [e-mail]