EI and water change

john arnold

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28 Jun 2018
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Hello

I EI dose but found some fish do not like 50% water change, marble hatchet fish, threadthin rainbows, and it sometimes kills them, is it ok to do 30% water change weekly, my Api kit says poss 60-80 ppm nitrates i know the kits are supposed to be crap but if i test the tap water and get a reading of almost zero and other tank that i do not ei dose is showing low ppm then it must be true that nitrate is higher in my EI tank ?
 

ian_m

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High inorganic nitrate levels (from EI dosing) are generally not an issue for fish, as fish can encounter varying nitrates levels naturally in their environment. I have accidentally run at 350ppm NO3 with no fish issues. You will need in the 1000ppm NO3 before levels become toxic.

EU tap water nitrate levels are a maximum 50ppm and are generally much less than this straight from the tap. Be careful about using a test kit to test for nitrates as nitrate test kits are easily affected by other ions present in the water and will certainly give false readings due to chlorine and/or chloramine present in tap water.

Organic derived nitrates, from rotting matter (fish, plants, poo etc) is another matter and the water can be highly toxic to fish not due to nitrates per se but the intermediate products namely ammonia and nitrites being toxic to fish. A well matured filter should remove these promptly and a well planted tank should remove the nitrates as well.

Never heard of tap water nitrate killing fish before. Usual fish killing culprits are massive sudden temperature change and presence of chlorine/chloramine in tap water. You are using warmed dechlorinated water for your water change ?
 

john arnold

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28 Jun 2018
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Somerset
High inorganic nitrate levels (from EI dosing) are generally not an issue for fish, as fish can encounter varying nitrates levels naturally in their environment. I have accidentally run at 350ppm NO3 with no fish issues. You will need in the 1000ppm NO3 before levels become toxic.

EU tap water nitrate levels are a maximum 50ppm and are generally much less than this straight from the tap. Be careful about using a test kit to test for nitrates as nitrate test kits are easily affected by other ions present in the water and will certainly give false readings due to chlorine and/or chloramine present in tap water.

Organic derived nitrates, from rotting matter (fish, plants, poo etc) is another matter and the water can be highly toxic to fish not due to nitrates per se but the intermediate products namely ammonia and nitrites being toxic to fish. A well matured filter should remove these promptly and a well planted tank should remove the nitrates as well.

Never heard of tap water nitrate killing fish before. Usual fish killing culprits are massive sudden temperature change and presence of chlorine/chloramine in tap water. You are using warmed dechlorinated water for your water change ?
Oh yeah of course, its heavily planted, here a pic to give you an idea, i am more careful with the temp water i put in, i used to do it by feel but now i use a thermometer even it takes lot longer now with the watering can ha
 

Attachments

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28 Apr 2017
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Sydney
Hi
Have a look at rotala butterfly fertiliser accumulation chart to see what lever your fertiliser can reach with different water change size.
30% water changes will be fine but adjust your fertiliser as well.
Your tank isn’t heavily planted, 1/3-1/2 ei dose should be fine for now.
The test kit shouldn’t be to far off what u measured.
I have had fish too that don’t like large water changes.
 

Simon Cole

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25 Dec 2018
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Buckingham
There is some debate about hatchet fish mortality. My personal belief is that almost all fish are imported from the wild, and that they naturally have a shortened lifespan due to a a natural tendency towards disease. This was reported in PFK magazine, but I do not have the study they mentioned. I have never had much longevity with this species, so now I just leave them to their natural habitat. I am more surprised to find that you are struggling with the thread-fin rainbows John. I support what others have said, that unless your local tap water is contaminated with pesticides etc, that regular water changes under a half-dose regime is unlikely to be a problem.
 

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