# Excel ruined my nitrogen cycle



## Lord Nibbler (Dec 22, 2005)

I don't know how, but today after I had added Flourish Excel yesterday, my nitrites spiked. I lost my 3 beautiful yellow rainbows. Absolutely nothing else had been done to the aquarium, the fish even had a smaller than normal supper the night before. My other 37 gallon also spiked but fortunately everything survived.


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## DJKronik57 (Apr 17, 2006)

Excel, as far as I know, has the potential to re-cycle your tank in higher doses. This sounds like what happened to you, it must have killed off all or a significant portion of your beneficial bacteria, causing nitrites to accumulate out of control. There's not much you can do except wait for the bacteria to grow back. I'd lay off the Excel for now. Did you add the recommended dosage? You may want to do a water change as well if you haven't already.


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## BryceM (Nov 6, 2005)

How densely planted is your tank? Planted tanks do develop a bacterial population, and in my opinon, this plays a vital role in maintaining a well-balanced tank. However, if you have a large plant mass, the net nitrogen balance is usually negative. This means you actually need to add nitrogen (KNO3) since the plants actively remove it from the water. There is almost never any free ammonium available for the bacteria to convert to nitrites.

If you have a high fish load, feed heavily, and have a small plant mass, then your tank may be relying on a nitrogen cycle and Excel, or a similar toxic compound could upset the balance.

How much Excel did you add?


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## Mud Pie Mama (Jul 30, 2006)

So sorry to hear about your rainbowfish, they sure are a beautiful fish. 

I have six yellow rainbowfish who are in a heavily planted 46g tank. I daily dose 4ml of Excel. However I use a medicine droper made for giving medicine to babies so the measurement is very accurate. I do not like using the cap for measurement.


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## Lord Nibbler (Dec 22, 2005)

I didn't use a medicine dropper or anything to measure precisely, but at most it was 120% of the dose. I hadn't added any for probably 2 weeks as I've been working like a dog and been forgetting  

A few water changes and days later, its back to normal. There were some planaria that seemed to outbreak as well. Not a ridiculous amount, but they were noticable. 

The aquarium (was) moderately heavily stocked. Not way heavily, 5 rainbows, 2 ottos and 6 kuhlis. Its moderately planted: swords, limnophila and red ludwigia.

The nitrite levels had spiked (when I took the reading about 20 hours later) to 0.5ppm. I hadn't taken a nitrate level before adding Excel but it typically hovers around 10ppm: between the fish and water changes it normally stays around there.


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## Mud Pie Mama (Jul 30, 2006)

Lord Nibbler said:


> I didn't use a medicine dropper or anything to measure precisely, but at most it was 120% of the dose.


This may have been the problem, I think if you were 'guestimating' the dosage visually instead of with an accurate measuring spoon it is very easy to overdose!

I'm also wondering if you were attempting to add the recommended daily dosage or the amount for after large waterchanges?

For my tanks I always round down to the next full hundredths: ie., 10, 20, 30. I do this to account for the water volumne lost from substrate, driftwood and rocks. So for instance when dosing my 46g tank, I dose for a 40g. If you take the same idea on a 37g you would dose for 30 gallons. With the daily dosage of Excel (5ml per 50gal) you would want to use 3ml for 30 gallons. This amount is actually a very small amount, 3ml is just a smidgen over a *HALF teaspoon!* I believe most people would have a very, very difficult time to accurately pour just a half teaspoon of product out of a bottle without getting too much.

You also mentioned your demanding work schedule was interupting your tank routine. Believe me, I do know that many things can overwhelm us from time to time. I've found I can skip or delay a weeks water changes but if I start to skimp on feeding the plants the whole balance of my closed ecosystem can go haywire. I think the only way you can chance this is if you have a soil substrate in a slow growth environment.

Let me share my little secret, by far the easiest ways for me to remember to do those tedious daily tasks is if I tie it together in my brain with something else I have to do. So...first, I chant this mantra: "Feed the Fish, Feed the Plants....Feed the Fish, feed the plants....Feed the..." Hopefully you remembered to feed those fish during those two weeks ? The second thing: make it very quick and easy to do. Right next to my jars of fish food I keep my premixed solutions of ferts and Excel along with a dedicated measuring dropper in their own small tray.

I know about work demands, I work swing shifts. Some days I'm at work until 11pm, other weeks I have to be there by 6AM! Arghh! On the days I go in by six here's my routine: First, "COFFEE, COFFEEE, coffee!" Then, waiting for coffee to brew...start smelling the coffee...okay, now mantra: "Coffee Brewing, Feed the Tank....Coffee Brewing, Feed the Tank, and Feed the Fish, Feed the Plants..." Reward: nice hot cup of coffee! If tied to something else and I make it a ritual with a reward then even on the most hectic days I'm pretty good about getting it done.

I hope this may help a little.


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## Craig Tarvin (Jul 26, 2005)

I don't think that Excel is to blame. So many people, myself included, have used several times the recommended dose for several days in a row without experiencing that type of issue. Especially since you hadn't used any in a while and only used 120%.


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## Lord Nibbler (Dec 22, 2005)

Actually it hadn't been after a large waterchange. The aquarium with the deaths is typically the cleaner (less stocked) aquarium and doesn't get as massive of changes (usually about 20% every 2 or 3 days).


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## tkos (Oct 30, 2006)

Did you see the nitrite spike after you found the fish dead or before the fish died?


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## Salt (Apr 5, 2005)

Nitrite spikes are typically caused by low dissolved oxygen.

Flourish Excel is a reducer and will lower dissolved oxygen in the tank. If you already had borderline DO levels, Excel may have pushed it too far.

I personally feel too many people underestimate the importance of dissolved oxygen, and don't run airstones because there is a belief they are gimmicks or outgas all of the CO2. If you have a HOB filter (hang-on-the-back filter like an Aquaclear), you can modify it with a Dremal tool so you can put an airstone in it. Its effect on CO2 outgassing is minimal.

DO levels also go down during lights off when photosynthesis stops. I personally run airstones in my tank on a timer at night, an run an airstone in my Aquaclear (again on a timer) during the day.

It also seems I've been reading a lot of threads lately where the user has a problem with Flourish Excel, and they then admit that they overdosed it... in some cases severely. Some people buy the 2 liter size, which has instructions regarding "capful" but that's in reference to the 250mL size cap. So they use the 2 liter cap and for some reason decide to overdose at twice the amount, but with the 2 liter cap they end up overdosing by 5 times the amount. I personally feel people should be following the label... 1 mL per 10 gallons, and 5 mL per 10 gallons *only after a 50% water change*.


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## Lord Nibbler (Dec 22, 2005)

I don't measure DO. The fish seem ok the rest of the time, although that doesn't give a good estimate. They did really perk up when I put in an airstone while the water was cloudy. I always heard bad things about agitating the water and CO2 so I typically don't run an airstone.

The spike was before the dead fish. In any case, they were really freshly dead at the time of the reading.


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## AndyT. (Jun 28, 2006)

Salt said:


> Nitrite spikes are typically caused by low dissolved oxygen.
> 
> Flourish Excel is a reducer and will lower dissolved oxygen in the tank. If you already had borderline DO levels, Excel may have pushed it too far.
> 
> I personally feel too many people underestimate the importance of dissolved oxygen, and don't run airstones because there is a belief they are gimmicks or outgas all of the CO2.


Salt has summed up my reation perfectly. As I read what happened I was thinking that it might well have been the DO levels that killed the fish.


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