# Nitrates uptake



## R0bert (Jan 23, 2006)

Hi,

My tap water is extremely high in nitrates (40-50ppm) and I was wondering how much nitrates do plants use up in a week? I've been reading about the EI, and I'm not quite sure I understand, but do people only add about 10-20ppm NO3 a week?
I'm hoping the plants are going to be using more nitrates than 10ppm as I'm adding more with every water change. Especially as I don't have a high tech tank I'm wondering if the NO3 uptake is going to make any difference at all? 

I've got approx 30 gallon (US) with flourite/gravel, 2x36W PC lighting and a DIY Hagen setup.
I dose Flourish Excel 2.5ml/day and Kent Freshwater traces 5ml/2 days.

I filled the aquarium with plants in one go two weeks ago and the nitrates haven't changed much.



Rob


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## acbaldwin (Nov 3, 2005)

It could be your test kit...
One test kit of mine reads 80-120 ppm NO3 in the tank, the other reads 30-50 ppm. The fish look fine to me. For an accurate test, I understand you can call the water company and ask.


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## R0bert (Jan 23, 2006)

The test kit's old but within the expiry period on this website that has test kits expiries on. I'm considering getting another kit anyway. I'd like one that has more color ranges on it. Mine is the API one which has 6 colors of which the last 3 look almost exactly the same. Any suggestions for a good brand?

One of my fishes died from swim bladder which may have been caused by excess nitrates and another one is starting to show signs of it too.
That's part of why I'd like to get the plants going.

edit: I forgot to mention the water company allows up to 50ppm nitrates here and I tested the test kit using some Evian water and it seems about right.


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## acbaldwin (Nov 3, 2005)

Honestly, I don't trust any of them really, outside of the high end kits like LaMotte. Most of the time they seem right, but for the last month and a half my nitrates have been off the chart with one of my kits, so I really just go with what the fish tell me. I'm not crazy, am I?
As far as the uptake rates go, that's the one thing about EI that I don't understand either. I've got a super low-light, low-tech tank, so I don't think the ferts are the limiting factor in mine. Perhaps the .75 wpg I have on my 55 gal is the problem?


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## zig (Jul 3, 2005)

R0bert said:


> One of my fishes died from swim bladder which may have been caused by excess nitrates and another one is starting to show signs of it too.
> That's part of why I'd like to get the plants going.


Your fish getting swim bladder is probably caused by a bad diet rather than high nitrates, high nitrate levels will not cause swim bladder not to my knowledge anyway but a bad diet will.

Fish that are fed a diet of mainly dried flake or pellets are suspectable to swim bladder, try and vary their diet, if the fish that you suspect may have swim bladder is still eating try and feed it some shelled peas or frozen Daphnia this can sometimes help or use a specific swim bladder medication.


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## plantbrain (Jan 23, 2004)

You can simply add K2SO4 in place of KNO3.

This will add the K+ without the extra NO3.

The rest of the dosing will be the same.

More light and more CO2/Excel= more NO3 uptake.

If you did a weekly 50Water change, that would add 20-25ppm or so to the tank each week. It's unlikely this tank will use more than 10ppm a week.

So you could go for once every 2 weeks for a 50% water change.

That would keep things lower.

Regards, 
Tom Barr


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## MossyLady (Dec 18, 2005)

If your tap water is really that high in nitrates, you might try diluting your tank replacement water with some distilled water, or you may use a nitrate absorbing pillow like nitrazorb. 

Also, cuttings from house plants, like Dracena, Pothos or Philodendrums, that will root in water, may be set into a HOB filter. They drink up nitrates wonderfully. (Just make sure the leaves are above the water.) I've read posts from folks who routinely run their water through a modified flowerbox-full of such plants suspended above the tank.


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## R0bert (Jan 23, 2006)

Tom, that's the exact answer I was looking for. Thanks. I'll reduce the water changes and see if I can get the levels back down somehow.

Zig, you're probably right. I have been feeding peas once a week, but now they have a constant supply of tasty veg too! I'm going to stop using the pellet food the fishies got for Xmas to see if that makes a difference.

Mosslady, that's an interesting idea about the house plants. Unfortunately my filter is internal. I was thinking about the Nitrazorb, too. I shall give it a try


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## chiahead (Dec 18, 2004)

I think Tom was trying to say fertilize once every 2 weeks and do weekly 50% water changes, although I am confused after re reading it several times.


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## plantbrain (Jan 23, 2004)

Yep, just wait 2x as long to do the water changes.
Then dose K2SO4 instead of KNO3.

That way the plants will reduce the NO3 over a longer time, you should remove nearly all the NO3 by the end of 2 weeks.

Adding NO3 remover does not provide much control if you add it to the tank, this could bottom out the NO3 and you not know it. I'd opt for the RO/DI water mix.

Regards, 
Tom Barr


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## R0bert (Jan 23, 2006)

Tom,

I've read several posts here about adding more phosphate to increase nitrate uptake. The tap water phosphate is around 3 ppm. Should I add more phosphate to match with the nitrate? Eg. NO3 = 40 so PO2 = 4+?

BTW, I checked out the Tropical Fish Centre website you suggested. Lots of useful info there. Thanks!


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