# Biological filter steals micronutrients - tell me that i'm wrong or not



## kekon (Aug 1, 2005)

I have been encountering many issuses with micro fert since i increased biological media in my canister filter. This is my new problem after i managed to defeat stunted tips in my tank.
It seems to me that the higher the volume of the media the more intense chlorosis appears on higher parts of plants. The chlorosis resembles Fe deficiency but at closer look one may notice that the whole leaves are pale green or light green-yellow (when only Fe is deficient not all the parts of leaves are chlorotic). Despite dosing heavy iron doses to raise Fe up to 0.5 ppm nothing was improved. Additionally, growth is very slow but there aren't any burned or stunted tips or deformed leaves. Changing single micronutrients (Zn, Cu, Mo, Mn) doesn't work (but none of micronutrients are overdosed). When i removed my Eheim 2213 and installed new 2215 with huge amount of biological media (i always use Eheim Ehfisubstrat which is one of the best on the market and very efficient) things went even worse. The chlorosis was much more noticeable. This is not due to Mg deficiency.
Increasing Mg from 8 ppm to 17 ppm didn't help (Ca was 30 ppm) ! In a typical planted tank such values (30 ppm Ca and 17 ppm Mg) should cause curly leaves within 2..3 days but it didn't happen ! I don't understand it at all. 
Anyway, i suppose that biological media may destroy micronutrients added to my tank because i can't find any other cause of the problem. This is not caused by too low NO3, K, PO4, Ca and Mg.
Dues to its high porous structure it seems to me it can absorb some nutrients from the water.
Did you notice such phenomenon in your tank ?


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## Freemann (Mar 19, 2004)

Maybe try increasing the urea you add, bigger biofilter more ammonia consumption, plants get chlorotic from lack of Nitrogen in a form they can absorb, sounds possible. Chlorosis is caused from nitrogen deficiency as well.


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## kekon (Aug 1, 2005)

I will remove some media from the filter but it seems adding more N doesn't help. Nitrogen deficiency shows up as yellowing on older leaves but i notice chlorosis on new leaves only. When 10 ppm NO3 was reached the situation remained the same. Anyway i will increase urea content in my daily fert (and maybe more NH4 as well). I thought of some toxicity that can be the cause of the chlorosis but i couldn't find its source (contaminated salts such as KH2PO4, KNO3 etc.)


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## Champagnero (Aug 7, 2006)

Hi,

here in Germany many plant enthusiasts don't use lots of bio filtration media. Especially filter media like siporax or Ehfisubstrat (i think they are the same , or?) have a negative impact on the micronutrients and can even influence the macronutrients.

Therefor some are even running without a filter (only using powerheads or totally without filter media) or they only use blue filter foam as filter media.

I for myself had similar problems and more nitrogen cured the chlorotic growing tips. In the past week i had some problems with cloudy water due to bacteria or whatever and introduced seachem purigen and lots of filter wool. Purigen not only removes tannins etc. it removes Nitrogen "waste" (read that some days later...) and my plants got REALLY chlorotic in only 3 days. The growing tips of rotala sp. green became white. I dosed kno3 in that time around 2-4 mg/l per day. Now i removed the purigen and the filter wool some days ago and dose urea besides some kno3 and the plants are recovering slowly.

Best Regards
Tobi


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## kekon (Aug 1, 2005)

This is good news. My tank volume is 200 liters and the filter is Eheim 2215. 2/3 of filter colume is filled with Ehfisubstrat... There is really plenty of it.
I should remove most of it. It can work as activated carbon and remove most of micronutrients. But what will i do if it doesn't help ? I can only shoot myself then...
When i had 2213 and low amount of biological media i never had problems with chlorosis.


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## Freemann (Mar 19, 2004)

Well I can see N chlorosis in young leaves as well Kekon I think N deficiency is still something to target for. I have a huge biological filter with emersed bioballs and yes I add tons of Fe, Te plus urea to keep plants happy and green.


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## kekon (Aug 1, 2005)

It may suggest that plants need plenty of urea/NH4 despite it seems there is enough N from NO3 (it's about 6..7 ppm). However i added KNO3 to raise NO3 to 10 ppm but it didn't help much. I will remove most of bio media and add more urea and see what happens.


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## Freemann (Mar 19, 2004)

> It may suggest that plants need plenty of urea/NH4 despite it seems there is enough N from NO3 (it's about 6..7 ppm)


Exactly Kekon this is what I am trying to stress and which I consider of the outmost importance, you yourself has dug out the article on beans that I have linked to, on the urea versus NO3 thread, I suspect it all has to do with bioavailability of N and is somehow linked with Ca absorption of the plant but I can't be sure of this detail, it seems to me that somehow plants are no able to accumulate N throu NO3 this would explain the multitude of problems and the constant yellowing I had with even 30 -40-50 ppm of NO3 through EI they just can't absorb and convert NO3 to ammonia somehow.


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## TortoiseBoy (Dec 30, 2004)

Kekon,
Thanks so much for sharing the results of your tank. I was curious about a couple of things you said in your first post. One was that you said you had solved the problem of stunted tips. Did you reach a conclusion about that in your other thread and I missed it? What did you do to solve this problem? Also, I was curious about your comments about the Ca and Mg causing curling in the leaves. Did you mean that the values you state were too high or too low in order to cause this curling?

I recently started dosing via PPS-Pro and I am thinking that I am having problems with defiencies in some of my plants. The curling in new growth in my L. var Cuba especially seems to indicate a Ca deficiency, but I added quite a bit of CaSO4 and it still seems to be happening. I am dosing per instructions of PPS-Pro (about 9 ml of macro and micro solution per day before lights come on). The curling in the Cuba seems to get worse as the plant gets closer and closer to the lights (makes sense). My water is also soft - about 2-3 dkh and 2-3 dgh. I have a suspicion that my problems are connected to your work on the uptake of nitrogen and calcium being connected in some way. Do you have any thoughts on the subject? Thanks very much!

TB


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## kekon (Aug 1, 2005)

The major factor which i found to be the cause of stunting, curling and deformations is too high NO3 and too low K - especially if the two exist simultaneously. Higher NO3 is more harmful at low GH. If there's high NO3 (10 ppm or more) and low K (say, 10 ppm) adding much Ca will not help at all. There was 25 ppm Ca in my tank and adding extra 20..25 ppm Ca didn't work. First, you have to add more K (if there's too little in your tank; adding about 15 ppm K should be fine) and to lower NO3. In very soft water (GH 3..5) 5 ppm NO3 may be enough for most plants. High NO3 doesn't hurt if water is hard. 
When it comes to Ca:Mg ratios it may depend on GH you want to maintain. I kept 2:1 at GH = 2 and it worked well. In harder water it seems "old and good" 4:1 is fine. I also kept 3:1 and it worked as well. Anyway, i recommend to set 4:1 ratio. This is the most common. I think it would be good to add more Ca and Mg to your tank to reach GH = 4.
I also found that adding some NH4 or/and urea helps at low GH. In this way one can maintain very low NO3 and good nitrogen supply. SO4 levels don't have any particular effect on plants. I checked low (20 ppm) and high (110 ppm) SO4. As with low SO4 so with high SO4 didn't change anything.


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## Champagnero (Aug 7, 2006)

Hi Kekon,

have you solved your Problem with the chlorosis?

Best Regards
Tobi


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## kekon (Aug 1, 2005)

No 
When i removed 80% of the bio-media (Ehfisubstrat) it helped somewhat but it was far from perfect.
The problem appears after adding more K. It's not Fe, Mn, Zn etc. deficiency - i examined all the micronutriens but adding each of them doesn't help.
Last week i did 65% water change and did not add K at all. After that, it was no more than 10 ppm K in the water column. Four days after water change plants got beautiful, rich colors. I was happy.
However, i noticed there was not enough K so I added about 10 ppm K. Two days after adding K plants became very pale again. The chlorosis always appear after adding K. This occurs on youngest leaves only. Adding Mg doesn't help much. I've just raised NO3 to 10 ppm but i doubt it will help (anyway, i have to wait a few days to see the effects)


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## Leonard (Mar 4, 2007)

I had problems with pale tips some while ago. I don't longer have this 160liter tank, but I added very much micros (and other ferts too) but the tips of my plants didn't change colour. I may have overdosed the other ferts too and that may also be the reason which made the plants blocked to consume any of the chemicals. Or maybe too low CO2 levels, I don't exactly remember...
However, I checked my external filter (TetraTec EX1200, with around 6-8l volume) and the filtermedia (Eheim Ehfimech) was covered with a hard dark red-brown layer of something. I belive this was the micros from my ferts.
Also my substrate (ordinary sand) in this same tank coloured from black to brown-red (not totaly, but mainly nearest the bottom) and I belive the ferts was caught here too.
The planted tank I run now have slight harder water (I use Eco-Complete) and I haven't noticed any lack of micro yet. I haven't keeped it very long time and that may be a reason. I also have more stabile levels of nutrients.

I love to read your interesting threads!  Keep up the good job!


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## kekon (Aug 1, 2005)

> I had problems with pale tips some while ago. I don't longer have this 160liter tank, but I added very much micros (and other ferts too) but the tips of my plants didn't change colour.


You are absolutely right. If there is too little micro fert plants get pale but the same happens when we overdose micros. Sometimes it's very difficult to differentiate between excess and deficiency of micronutrients.
I noticed that the main cause of chlorosis is boron and copper. These two micronutriens are extremely harmful when overdosed. Also adding too much iron (without other micronutrients) causes chlorosis.


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