Installing new HOB mid-cycle?

[moboe]

Greetings,

I started my 20g tank almost 2 weeks ago with 2 small Zebra Danios. 3 days later, I added 2 long finned Leopard Danios and live plants. So far, ammonia and nitrite levels have remained steady (after ammonia spiked a bit) and I've planned on waiting another 2 weeks to add more fish.

My question is, my tank came with a Whisper 20 filter, and that is what has been running since I started the tank. I've purchased a Penguin 170, and am giving the Whisper 20 to a friend, but don't know when the best time to switch the filter is. If I switch to the 170 now, will I have to start my cycle all over again? I plan on rinsing the new filter in old tank water...will that be enough?

Thanks in advance.

Margaret

[aquariumfishguy]

Add the new filter while the old one is running. Dont take one out and then add the other or you could be looking at a severe mini-cycle, or possibly starting over again. I would wait a good 4 weeks after adding the new filter to hand the other one over.

[Hound]

Yep what he said.

[moboe]

Thanks, AFG and Hound, for the information. I thank you, and my fish thank you!