# Nitrite spike after cleaning filter



## sorenH (Mar 26, 2018)

I cleaned my filter media using tank water and poured out the dirty water in the filter. 2 days later, my nitrites are at .5 ppm. Does this mean my filter bacteria are dead?? If not, is there something I should do (other that stop feeding for a couple days)?


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## nodima (Oct 3, 2002)

What kind of filter? Did you refill with tap water? How long has the tank been running?

Did you add more fish?


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## sorenH (Mar 26, 2018)

It's an fx6. I was careful to rinse the media only in dechlorinated tank water. My tank has had fish in for between 1 and 2 months, and since my fishless cycle I have not seen any nitrite. The last time I added new fish was 2 weeks ago.


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## sorenH (Mar 26, 2018)

My nitrite has dropped to 0 after 2 days with no feeding, so the outlook is ok I think.


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## alwayssellin27 (12 mo ago)

sorenH said:


> My nitrite has dropped to 0 after 2 days with no feeding, so the outlook is ok I think.


Did you ever figure out why you had nitrites? I'm in the identical situation now. Just curious


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## fishboy75 (Jan 16, 2020)

If you have the one filter and you did too thorough of a cleaning you could definitely disrupt your beneficial organisms and possibly create a mini-cycle. Less is more when maintaining filters, especially canisters. I don't open mine unless there is reduced flow. I have 1 FX6 and 2 FX5's on my 125 that I had to setup when my 265 started leaking. That was July 4th. Just last week one filter needed to be cleaned. That's almost 9 months without cleaning. And what do I do when I open it? Put the outer sponges in one bucket of tank water and all the biomedia in another bucket. I used to squeeze out all the sponges but I read you lose alot of beneficial organisms when you do this. So I pretty much just swish them around in the bucket and put them back in. Bio media I don't even swish around. If i have filter floss or any type of mechanical media in there I chuck that and add new but all three of my chambers are pretty much bio media. I wouldnt even rinse out the canister but I get some sand accumulated in the bottom so have to get that out before it gets to the impeller. Hope this helps out


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## alwayssellin27 (12 mo ago)

I think I did just that caused a "mini cycle " after 2 days of not feeding I'm back at 0 nitrite and 0 ammonia. Nitrates are always through the roof though.


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## fishboy75 (Jan 16, 2020)

When you say through the roof how high are you talking? The easiest and quickest way to bring it down is by water changes. If it's been awhile since your last one, say months, then start with a partial one of 25% and do that daily for a few days/ week. Once nitrates are down to a decent level say 40 or less, then you can increase the amount you take out. Theoretically, you can do a 100% water change if your tap and tank water have the same water parameters. Would be wise to invest in a total chlorine kit as well and check your tap water before water changes. This way you know if you need to increase your dechlorinator if your water source has changed their chlorine/ chloramine levels. Once you get your nitrates under 40 you might find that you can do a 75% water change once every 2 weeks and maintain a good level. But every tank and fishkeeper is different ( amount of fish, amount of food, biofiltration etc) so you have to test to see how long you can go between water changes.


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## alwayssellin27 (12 mo ago)

Like it would seem the highest, below starting from the left is my livingroom tank with nitrite, ammonia and nitrate. Middle is a hospital tank i started up so its cycling (showing nitrite and ammonia. Third is my other tank same as the first, the blood read viles are nitrates. I have done water changes frequently of 25% -50%. Nitrates are just ALWAYS high regardless of what i do.


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## DJRansome (Oct 29, 2005)

Try working gradually up from 25% water changes to doing them 50% or even 75% weekly to keep the nitrates under 20ppm. Shoot for 10ppm after a water change.

You can space out your water changes every 12 hours to get from 25% to 75%...so 25% today, 35% tonight, 45% tomorrow am, 55% tomorrow night and 65% the morning after that. Then do your first 75% 12 hours later and see where your nitrates are.

I find it easier to just do a weekly change without testing...assuming your nitrates are at or under 20ppm to start with and your stocking is reasonable. I don't test and wait until nitrates are high to do a water change.


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## fishboy75 (Jan 16, 2020)

Agreed, once you get your nitrates under control and have a set schedule to maintain them you really don't need to test anything. Obviously, if you have sick or dying fish or the water is cloudy or smells its good to test and do a water change.


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