# Made a huge mistake changing biomax in cycled tank!



## Elvis (Dec 6, 2010)

I have a 75G tank with a fluval 304 and I wasn't the one who initially set it all up so I assumed that it was done wrong. The tank has been cycled I believe its been active for over a month now and I have just changed everything in my filter :-? I didn't know until now that my tank will have to cycle again since I changed all the biomax and put in new stuff. 

My question is what can I do now to prevent my fishes from dying?? I was thinking changing the water everyday and adding additional "nutrafin cycle" to it. Should I treat the tank like its day 1 now? I am so worried that my fishes are all gonna die I just picked up 5 tetras and 3 otos too :-(


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## shinybetta (Jul 3, 2010)

You should do more frequent water changes. Maybe a Gravel vacuum 70-80% once a week, and 25% every other day. I wouldn't be to worried, as long as you monitor the ammonia, nitrate, and nitrite levels with a test kit.


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## Byron (Mar 7, 2009)

Are the mentioned fish the only fish in the tank? If there are other fish that have been in there during the previous month you mention, then bacteria has probably colonized other surfaces in the tank. But if no other fish, what was the source of ammonia to start the bacteria? And in a 75g there is greater room for error--unless the tank is full of other fish.

Byron.


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## Elvis (Dec 6, 2010)

The fish in the tank right now are:

11 Neon Tetras (5 added right before I changed the filter)
6 Guppies
3 Gouramis
3 Otos (added right before the change)
2 Red wag platy
2 zebra danios

I did a water change today, changed about 80L and added 50mL of "Nutrafin Cycle" to boost the bacteria growth.


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## Byron (Mar 7, 2009)

I wouldn't expect an issue, but monitor the fish. A partial water change will not hurt should they show any signs of problems.


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## Elvis (Dec 6, 2010)

Since I added the otos I didn't clean any algea in the tank so there is quiet a bit of that in there as well I don't know if that would help.


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## Elvis (Dec 6, 2010)

I tested the water today and it read

Ammonia 0.25
Nitrite 0.00
Nitrate 0.00

I believe this is a bad thing


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## Byron (Mar 7, 2009)

Elvis said:


> I tested the water today and it read
> 
> Ammonia 0.25
> Nitrite 0.00
> ...


I didn't see any of these numbers for previous tests, so it may or may not be something. What is your tank water pH? I ask because in acidic water (pH below 7) ammonia changes automatically into basically harmless ammonium, and test kits like API's read ammonia/ammonium together as ammonia. Also have you tested the tap water (on its own) for ammonia? Some tap water does contain ammonia, so it is useful knowing this.

Aside from the above, if the ammonia should rise (and in a basic pH above 7 in the tank) I would do a 50% water change.

You mentioned Cycle previously, and that shouldn't do harm. I have used it myself, though now I prefer the 100% live bacteria supplements like Seachem's Stability or Tetra's SafeStart. They help to seed the tank's bacteria.


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## Elvis (Dec 6, 2010)

I have been tracking the water for 3 days now and readings have been pretty steady. 

Its always Ammonia 0.25, Nitrite 0, Nitrate 5.0-10.0

I just finally tested the tap water and it turns out that it almost has more Ammonia than the tank water.
Reading was close to 0.50 definitely more green than the tank water.
If Ammonia kills fish should I do something to the tap water before adding it or will the filter take care of it? Also since I'm getting no Nitrite readings but am getting Nitrate readings does that mean my filter is established?


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## Byron (Mar 7, 2009)

Elvis said:


> I have been tracking the water for 3 days now and readings have been pretty steady.
> 
> Its always Ammonia 0.25, Nitrite 0, Nitrate 5.0-10.0
> 
> ...


This is now making sense, it explains the ammonia reading in the tank when you have nitrates.

I would recommend a water conditioner that detoxifies ammonia; there are several, just make sure it says this. Conditioners should work (at detoxifying whatever they detoxify) for about 24 hours. This handles the initial ammonia influx at a water change. Conditioners detoxify ammonia by changing it to ammonium, which as I mentioned earlier is harmless. Bacteria and plants use ammonium/ammonia interchangeably so by the second day the plants (if there are any) and bacteria should be fine at dealing with the added ammonia.

On the nitrite, probably. Unless there is also nitrate in tap water. I would test the tap water on its own for nitrite and nitrate, again just to know. And if you are using the API liquid nitrate test, shake regent #2 for 2 minutes (rather than the 30 seconds in the instructions), otherwise you may well get an inaccurate and high reading.

Byron.


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## Lolcat (Dec 6, 2010)

by the way, you said you have 2 zebra danios, they are a schooling fish, and require a minimum of 6


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