Could Dosing ferts cause a ammonia spike? - The Planted Tank Forum
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post #1 of 3 (permalink) Old 07-20-2011, 02:57 AM Thread Starter
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Could Dosing ferts cause a ammonia spike?

Hello All,

Let me begin by saying I am brand new to aquariums. I started my tank roughly a month ago, planting from the start, full bioload from the start with tetra safestart. About a week in from inception I started seeing my ammonia and nitrites read 0 consistently, these readings were like this until today.

Two days ago, I started dosing fertilizers based off a modified EI dosing regime for excel/medium light tanks that I gathered from Tombarrs site.

I started seeing ammonia levels at .5 ppm, and nitrite levels at .25 ppm today and am unsure of where these appeared from.

My question is this. Considering I am unsure if my aquarium is 100% cycled (since to me its plausible the plants were eating up the ammonia quicker than my fish could produce), would dosing kh2po4 and kno3 cause ammonia and nitrite spikes if my plants prefer the fertilizers over the waste provided by my fish and its food?

I gave my fish an extra bit of food yesterday and today (though nothing they couldn't finish); could this also be the sole cause of the spikes? Should I stop dosing?

I just did a 50% water change, and am uncertain of the relationship between ammonia plants and fertilizers.

Any insight would be appreciated.
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post #2 of 3 (permalink) Old 07-20-2011, 03:20 AM Thread Starter
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an extra bit of info,

I dosed .8g kno3 and .4g kh2po4 dry straight into the tank.
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post #3 of 3 (permalink) Old 07-20-2011, 03:22 AM
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I don't see how.

Plants prefer ammonia over nitrate/nitrite as their source of nitrogen and should readily absorb it. I don't see how adding other things plants need would impair that function.. if anything, it would increase it.

Some thing that may cause it.. an accumulation of waste in the filter or substrate, plants dying off due to light/CO2/nutrient deficiencies, more adequate fertilization causing algae to die off and no absorb ammonia (algae is good at that).

0.5 ppm ammonia isn't terrible. While not ideal and should be watched, fish can tolerate it. 0.25 nitrite would be no concern of mine since it's less toxic in the short term than ammonia.

Keep in mind, doing a water change will result in the presence of ammonia if your water source has chloromines. Chloromines are just chlorine that's bonded to ammonia. When you use conditioner to eliminate them, it breaks that up and releases small amounts of ammonia.
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