# Strong current killed my tetras?



## kid4life (Oct 23, 2011)

A couple days ago, my current Fluval U3 died so I bought a U4 (was planning on upgrading to a bigger tank soon anyways) to replace the U3. 

I put it in, the current was insanely strong but the fish seemed to be okay since they avoided the top area. The next day, I lost a lemon tetra and a cherry shrimp... I quickly removed the U4. I didn't know what to do and had no time to get another filter so i took my old filter, plugged it in and smacked it real hard and it started working again .. so i am back to the U3.. the following day another 3 lemons died.

wth is going on!!! i've had this tank running for a year and half before with no deaths till now


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## Tarobot (Jun 27, 2010)

did you use the same media from the U3 in the U4?

The U4 has 260gph, and if you have a 47g, that's roughly only 5 times turnover rate which is still ok and though tetras prefer slower water they are good swimmers.


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## kid4life (Oct 23, 2011)

no i used the new media that came with the U4.. i was thinking that there would be enough benifical bacteria in the tank already with 4 pieces of drift wood and heavily planted tank that it would be okay not to transfer the bio nodes and spounge/carbon .


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## Tarobot (Jun 27, 2010)

the plants will help a bit but the wood themselves aren't really pored enough to carry much bacteria. i would suggest to add an airstone and use Seachem Stability (you can't rly overdose this product). Bacteria needs oxygen to do the nitrogen conversion cycle and fish also need it to breathe but an airstone will inject air continuously thus satisfying both criterias. Stability is literally bacteria in a bottle.


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## gklaw (May 31, 2010)

I have a U4 as well, you could adjust the flow to come out from the top and bottom nozzle at the same time so the flow will not be so concentrated.


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## taureandragon76 (Apr 21, 2010)

Nothing to do with the flow at all, if you used all new media on the new filter then you don't really have any beneficial bacteria at all and your tank will cycle again. What you need to do is test your water and see what the levels are, I would almost bet that your ammonia and or nitrites are up.


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## kid4life (Oct 23, 2011)

i read up on seachem stability... since i put my old filter back in with the same media, do you think i would still need it? i know it would've definitely have helped if i used it when i put in the new filter, but now it seems it would be too late.. 

gklaw: im at work right now and cant test it, but does splitting the output from the top nozzle and bottom nozzle still allow aeration?


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## Tarobot (Jun 27, 2010)

bacteria dies roughly 20~30mins out of water so chances are it's all gone. can't really go wrong with stability.


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## SeaHorse_Fanatic (Apr 22, 2010)

As others mentioned, by not reusing the old media, you reset your tank and caused a mini-cycle. Most of the bacteria in our fw tanks live in the filter media, not in the water or on the surface of objects in the tank. Changing out the media completely removed the vast majority of your good bacteria. Now putting the old filter in after its been left dry and not running for a day or two means you're probably adding excess nutrients back into the tank.

In the future, when switching out filters, just take some of the old media and add it into the new filter/media to reseed.

Probably not what you want to hear I'm sure.

Anthony


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## kid4life (Oct 23, 2011)

ahhhhhhhhhhhhhh 2 more dead cherries and a rummy T_T what an expensive mistake!!!!!

Thanks everyone for the tip everyone !!

 well at least this will probably not happen again in the future. lesson learned.


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## Ebonbolt (Aug 12, 2011)

Tarobot said:


> bacteria dies roughly 20~30mins out of water so chances are it's all gone. can't really go wrong with stability.


I'd check up on that... I tore down a friends tank, transfered it over to my house, set it up, and added fish to it to cycle, but I never experienced a cycle. The entire process of tearing down, transfering, and setting back up took about 4 hours, and I used the same media, substrate, etc. I highly doubt bacteria would die after being out of the water for 30 minutes, otherwise, the last power outage would've completely reset all my tanks.

As for OP, the majority of a tank's bacteria reside in the filter. That's why you can instantly cycle a tank by moving a filter from a mature tank to a new one. To avoid a reoccurence of this, I suggest running two filters on your tank. There's no such thing as over filtering, and though the tetras do prefer slower moving waters, they don't mind a higher current either. Plus, as mentioned, you can always adjust the flow. By keeping two filters on the tank, you can remove or replace one filter without worrying about a mini-cycle, or worse, a reset of your tank.


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## Athomedad (Oct 8, 2011)

Definitely check ammonia levels before assuming your tank cycled again. Could be a toxin or disease?


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## kid4life (Oct 23, 2011)

hmm.. i did a test and everything seems to be fine, but nearly all my fish are dead now other than my plecos and shrimp and galaxy rasboras... for some reason.. they are perfectly fine.. still eat and everything as if nothing ever happened


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## Athomedad (Oct 8, 2011)

My only thought was that maybe one of the new filter parts/medium were contaminated or you had an aeromonas outbreak. I am by no means an expert but that was my thoughts. Sorry for your loss.


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## Gone Fishy (Apr 21, 2010)

Hello,

Just my two cents...., bacteria in your filter will not die if kept wet, I've had mine sit in buckets for one, maybe two days!! No ones tank is so clean that there isn't something for them to feed on if sitting in tank water, even with the occasional stir to provide O2. If it dries out, or is not kept wet then your time decreases drastically. I have to agree with the mod, new cycle killed your fishies, I have had neons intentionally group and swim from the output of my FX5, they are quick and built for speed.

Lance


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