Need help!

[Thatfishfreak91]

How will it take for this to work

It's a 55 gallon tank with a 20 gallon sump

 

[Thatfishfreak91]

Sorry i forgot to add this

 

[Mebbid]

It's hard to tell. If you are planning on a fishless cycle I would imagine it to be completed in 1 week at the very earliest. There are a ton of variables the come into play that determine how fast your tank cycles.