Can I add in new sump tank to existing canister filter?

[MIdol]

Hi,

I have a 150L marine tank with fishes and corals running for about 3 months. I'm currently using an external canister filter and wanted to add on a sump tank wet/dry filteration. Once i have setup the sump tank, can i add straight to the display tank running together with the external filter? Or i have to cycle the sump tank before adding the filter to the display tank?

[BFG]

I do not think you'll need to cycle the sump tank, but you need to prepare more water with the addition of the sump tank.

[MIdol]

Thank you BFG for the advise. In your opinion, won't there be a Nitrogen shock as the sump tank is new?

[BFG]

Where would the nitrogen come from from the bare sump tank? I would think the extra water volume from the addition of the sump tank might dilute whatever in the water column. Do not add newly made saltwater into your marine tank though.

[MIdol]

As the display tank has just sufficient amount of water, i have to add new salt water into sump tank to run the overflow.