Cycling after water change?

[shafiq_hossain]

I have a 75 gallon QT which I've cycled. Since I'm switching over to a different salt, I was thinking of doing a substantial water change before putting in any new fish. My question is will a substantial water change require the tank to go through a new cycle? Do the bacteria which neutralize the ammonia and nitrite float around in the water?

Thanks....

 

[jef4y]

No need to do a massive water change on switching salt. And no, you won't experience a cycle over a large water change. The bacteria is primaily contained in the rock & some in the sand.

 

[shafiq_hossain]

Dont have any rocks. Just PVC pipes. So, I can assume that the bacteria are attached to the PVC pipes? I would think that the bacteria may also be attached to sides of the aquarium. If that is the case, they would remain exposed to air when I do a water change. How long can these bacteria live without being in water?

 

[rdnelson]

I don't think you will have enough bacteria if all you have is PVC pipes and tank walls. You need some established media such as Live Rock, Live Sand, Bio Wheel or Matrix. Which ever way you go, it will need time to get established or yes, you will go through a cycle with or without the water change. JMHO

 

[shafiq_hossain]

My apologies. I forgot to mention that I do have a Fluval 406 Canister Filter running on the tank.

Edit: Good point. I was planning on puttting in some sensitive fish such as a Regal Angel and wanted to make sure the water quality was optimal. Additionally, I just came back from a 10 day trip during which time I had turned off the flow of water in my QT. I have turned it back on and has been on for about a week. So, having said all that, do you feel I should be fine doing a small partial water change?

Thanks....

 

[jennm]

If your filter was off for 10 days and no water flowed through it, or the rest of the tank, then any biological you did have, is now dead.

Have you tested the parameters of the tank now?

IMO you're back to square one, water change or no water change. You'll have to re-introduce beneficial bacteria.

Did you not notice a stink when you fired the filter up again? I've opened up some stagnant canisters and the stench is overwhelming.

Jenn

 

[shafiq_hossain]

Actually, I did not open up the canister. But I poured in a capful of ammonia to see how quickly it would get neutralized. After a week, no ammonia and nitrite.

 

[jennm]

Wow...

Not how I'd do it... but OK...