Water quality mystery: What's causing the ammonia?

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Barliman

Aquarium Advice Addict
Joined
Feb 20, 2016
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Location
Los Angeles, 3rd door on the left
Hi all,

I'm faced with a bit of a puzzle. I keep a 10g tank as a grow out tank for platys I harvest from my 20g, taking them to the pet store when they're big enough. The tank has been up a bit over a month. Here are the basics:

Substrate: none. Bare bottom.
Water changes: 20% daily, 30% per day over the last weekend, 40% tonight.
Fauna: nine juvenile platys, about 1" in size
Flora: floating anacharis and cardamine lyrata
PH: 6.8
Nitrites: 0
Nitrates: 5-10
Filtration: 1 AC 20, 1 medium sponge filter
Feeding: a variety of flake and frozen, no more than they can eat in two minutes.

The water was tested both with Tetra strips and the API Master Kit, and they agreed with each other. The tank was cycled from the start because I used an already-cycled sponge from another tank in the AC 20.

Water quality hadn't been a problem until about a week ago: I had given the fish their first meal of frozen bloodworms and, the next day, I noticed they were lethargic. Figured it was a "food coma." But, when two were still that way the next day and were hiding in the plants, I checked the water: ammonia was at 1.0. :eek:

I'd been doing 20% water changes daily since the tank was set up, and then increased it as described above. I can get the ammonia down to ~.25 with large water changes, then it creeps back up again. :banghead:

I'm baffled about the source: I vacuum the bottom with each water change, getting as much detritus as I can find. All fish are accounted for. Here are my guesses:

  • Perhaps the bacteria bed died? How I don't know, and it seems even odder because of two filters. Can cycled filters spontaneously fail?
  • Or, was it bad carbon? Two-three weeks ago, I had painters in another room of the apartment. To deal with possible fumes, I removed one sponge from the AC 20 (left it in the tank, though) and replaced it with a pillow of Fluval carbon from Petco. Is it possible that, in just a couple of weeks, the carbon was exhausted and started releasing toxins? I've removed it and replaced the sponge. If true, I should see a difference soon.
  • Evil spirits? :blink:

So, I'm keeping up the daily large water changes and trying to get the filters doing their job again. :facepalm:

Any ideas what may have caused this?

Here's a picture of the tank:
35763009194_5fb588e97a_k.jpg
 
Barliman, you are truely a dedicated aquarian. You are extrememly diligent regarding your tank maintenence and that might have caused your problem. The intense tank cleaning may actually be starving out your bacteria bed, causing a mini cycle. I made a rookie mistake a few months ago, cleaning both my A.C. filters at the same time during a weekly WC. The next day, lathargic fish on the bottom of the tank, some swimming against the filter current. A self inflicted mini cycle. It took a week of daily WC' s and careful feeding to get things back. Once you get your tank up and running normally again, you might consider spacing out your WC' s which will make more nutrients available to the bacterial bed making it healthier. Hope this helps.
 
Those are both intriguing possibilities: this started soon after feeding them the worms. I wonder if a bunch were sucked up the filter. Time to do a cleaning tomorrow.

And maybe I starved the BB, but I should think what gets sucked onto the sponge filter and into the AC would feed them. Still, maybe I am over-vacuuming the poop.

Thanks, guys. It's food for thought. (y)
 
Did you check your source water?
Honestly those platys are feeding the BB faster than you can clean but I have read about die offs.
 
Did you check your source water?
Honestly those platys are feeding the BB faster than you can clean but I have read about die offs.

Haven't checked in a while. I'll leave some out overnight tonight to test tomorrow. The same water, however, goes into the main tank, and it's shown no problem. Granted, it's larger and planted very heavily.

The filter gets a cleaning, too. Something being trapped in it sounds more and more possible. :fish2:
 
IMO you could not have straved the filter and then found ammonia?The filter would eat it...
Bacteria does not die fast from lack of nutrients ,but rather would become dormant/hibernate and quickly regenerate when a food source [ammonia ] was introduced.
I change water like you do and no harm comes to my rams,apisto,swordtails,acaras or guppies ?
I would just dose prime every two days and get back to normal 20% wc ...
 
So, we *may* have turned a corner. I came home tonight and first tested the water: ammonia at .25, which is where it was last night after the 40% change, and that in turn tells me I may have removed the source after removing the carbon bag last night. Did a 20% change tonight, still .25 afterwards, but I'm not surprised. As long as it doesn't go up again, I'm confident I can eventually eliminate it. (y)
 
So, it looks like my theory that exhausted carbon was releasing toxins was wrong: I came home and tested last night, and the ammonia was back up to between .5 and 1.0. So, I did a 40% change then and another tonight: ammonia is back to roughly .25. I've also been double-dosing with Stability for the last few days to jump-start a new cycle. That can take more than a week, though, so, we'll see. In the meantime, I'll keep up the daily 40% changes. (Twice daily on weekends)

The fish themselves are still showing distress: no clamped fins or rapid breathing, but they're very listless (nitrates read <10ppm, by the way) and timid, hiding where they can and panicking when I walk by. (Before this started, they would dash to the front to beg for food) They were a bit better after I changed the water, so it must be related to the water.

This isn't distressing, so much as it's puzzling: Why did the BB (apparently) die after several good weeks?

Regardless, the plan is to get the water clean enough so that they get healthy again, at which point I'll take them to my LFS. After that, I'll do a proper fishless cycle on this tank.

:fish2:
 
In my city... There's Ammonia in the tap water! Check your tap water. Also check chlorine levels in your water. If your on a sisters or well or ground water, they may be putting bleach in there as well, killing your filters ( it surprisingly not your fish? ).
 
In my city... There's Ammonia in the tap water! Check your tap water. Also check chlorine levels in your water. If your on a sisters or well or ground water, they may be putting bleach in there as well, killing your filters ( it surprisingly not your fish? ).

Thanks. I'm on LA DWP water, aka "liquid gravel." (Although the dKH out of the tap is surprisingly low in this area.) They put chlorine and (I think ) chloramine in the water, but I use Prime as a detox.

I tested the tap water the other day, and there's no ammonia in it. Also my other tank isn't showing any distress, yet I add top-off water from the same source. The die-off of the BB in the 10g is going to forever be a mystery, I think.

The good news is that, with a 40% water change yesterday and another this morning (to be followed with another this evening), the fish all seem happy and healthy: actively swimming, rushing to the front glass to beg for food, and showing a good appetite.

Hopefully I can get the filter reestablished soon. :fish1:
 
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