Adding new filter to Established tank?

My current 20g saltwater tank that has 4 and a half - 5 Kilos (10 Pounds) of live rock with 2 corals and inverts has been established for about a year now, I don't run any filter but I do water changes twice weekly, And the tank is quite clean and the corals are very healthy.

I'm looking to add a Marineland Penguin 350-B Hang on Filter To my tank but I don't want it to cycle again.... Especially with the corals in it. Is there ANY way to add a new filter to a tank with it causing another cycle?

I've read up that with enough Live rock (Which is basically another form of filtration) can stop the New filter from cycling again... Am I wrong? I need help. Thanks!

Otherone said:

It doesn't work that way - add a sterile new anything and the b+b moves into it not recycles

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Would the Live rock not count as a good support over the new filter?

So what do you suggest? What does everyone suggest?

jtietz said:

i hate hang on back filters for saltwater. its a crash waiting to happen. nitrate trap then when you go to clean it booom. go with a hang on back protein skimmer or a sump/refuge and protein skimmer. i prefer the sump the more water the more stable

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I'll be saving up for a HOB Protein Skimmer as well