# Potassium deficiency?



## miku

Hello,
I have problem with my Hygrophila corymbosa as you can see on attached picture. 
I want to ask if you think it is a lack of potassium. I ask because I'm adding about 20ppm of potassium from K2SO4 every week when I make water change. Is it not enough? I have to add more?

Thanks


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## GHNelson

Hi
Could be a combination of deficiencies.
Magnesium could be one.....its hard too pin point,can you give us a run down of your set-up and your fertilzer dosing regime..are you using Co2.
hoggie


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## miku

Hi Hoggie,
thank you for your reply. It is a 40 litres tank with Eheim Classic 2211 filter and 18 Watt lighting. I use quartz with osmocote as a substrate. Tank is running for nearly a year. In the tank I have 5 corydoras, 6 galaxy rasboras and unknown number of red cherry shrimps   
As I said I add cca 20 ppm of potassium once a week when I'm doing the 50% water change.  I'm doing it once a week and I use normal tap water. I'm also adding 0,25 ppm of Fe daily. I don't add NO3 nor PO4, because I think that the fish provide enough of it. Nor do I add Mg because the tap water is hard (15 DGH). I also dose 3 ml of Easy Carbo daily.


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## ceg4048

Hello,
         Holes in plants are always caused by poor CO2. You need to add more.

Cheers,


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## ian_m

The U shaped holes I suffered in some of my plants (mainly swords) were caused by my clown loaches. Caught them in the act a couple of times.


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## Ady34

Hi Miku,
from your picture it looks as if the leaves are yellowing but the veins are remaining dark, which as Hoggie suggests, is a sign of magnesium deficiency, and even though your water is hard, is it hard due to Ca or Mg content, it may just be high in calcium with little magnesium? 
Pinholes can be potassium, but diagnosing is difficult unless your experienced ive found, as the general concensus as Clive has said is that 99% of the time to c02 is blame. 
Heres a link to James Planted tank guide with a list of deficiencies and possible causes:

http://www.theplantedtank.co.uk/deficiencies.htm

Trial and error may be the only way to get a conclusive answer. Maybe try upping carbon availability as a first step, if that fails try adding extra potassium, and then maybe Magnesium?
18w of lighting over 40l is quite high without n and p dosing also. Id have thought 3ml of liquid carbon would be more than enough, but maybe reduce lighting intensity if that is an option.
Cheerio,
Ady.


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## dw1305

Hi all,


> from your picture it looks as if the leaves are yellowing but the veins are remaining dark, which as Hoggie suggests, is a sign of magnesium deficiency, and even though your water is hard, is it hard due to Ca or Mg content, it may just be high in calcium with little magnesium?


 I agree with "Ady34" & "Hoggie", I think this is a nutrient deficiency, magnesium (Mg) is a possibility, but it is most likely to be nitrogen (N). 


> I don't add NO3 nor PO4, because I think that the fish provide enough of it. Nor do I add Mg because the tap water is hard (15 DGH).


 Nitrogen, phosphorus and potassium (N, P & K) are the mineral macro-nutrients that plants require most of, really even this is a bit of a generalisation because they need about x10 as much N and K as they do P. All the other nutrients are micro-nutrients, although the plants requirement for magnesium (Mg) will be x100 of their requirement for potentially toxic elements like zinc (Zn) or copper (Cu). 

As you don't add any nitrogen, but you do add potassium, it is far more likely that nitrogen is deficient than potassium (which you add) or phosphorus (which the plants need a much smaller amount of). I'll ignore CO2 levels as a variable because I don't add it, and I have low. tech tanks with healthy _Hygrophila corymbosa_ at ambient CO2 levels. 

Magnesium levels are low in a lot of the UK's rocks, and because of this also in the UK's tap water, details here: <http://www.ukaps.org/forum/viewtopic.php?f=11&t=22154&hilit=+magnesium>, so it is possible that magnesium is deficient and again as suggested "interveinal chlorosis" is a symptom of magnesium as well as nitrogen  deficiency. 

Even though this is a submersed plant, you can still use the "Duckweed Index" approach to fertilisation, where you add KNO3, and then if things don't improve MgSO4.7H2O, followed by a complete fertiliser mix if growth is still unacceptable. 

Have a look a these posts, in the first you can see _Hygrophila corymbosa_ <http://www.ukaps.org/forum/viewtopic.php?f=21&t=24109&p=247151&hilit=Duckweed+index#p247151> & in this one there are <http://www.ukaps.org/forum/viewtopic.php?f=17&t=14400>.

cheers Darrel


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## NatureBoy

the 'duckweed index' is genius for checking out whether the issue stems from CO2 V mineral deficiency.   

I believe H Corymbosa needs a lot of CO2 and other nutrients because it's a fast grower given a light level.

I second the N/P/Mg leaf color / interveinal diagnosis.

Just a thought, could the brown spots be iron deposits in the leaves brought about by the .25pmm FE daily? I'd go easier on isolating the Fe and K needs of the plant, and concentrate on CO2 and ensuring that the other macro needs are met.

My personal view is to try and maintain a *constant* but very low K concentration in the water, not more than 1ppm say, by small daily doses. High K makes no difference for most plants, but time and again I can induce calcium like deficiencies...curly new leaves on healthy plants such as L arcuata, R macranda, etc if I up the K. I know this observation gets shot down time and again in favour of not enough CO2 (particularly as the plant grows toward the light, and needs change, etc) but I'm taking about plants that were showing beautiful red well formed leaves (and now continue to do so) since going easier on the K...by no means a scientific observation I know, and I'm going a touch off topic.

I use tapwater solely, called "moderately hard" by water company, high Ca, really low Mg, High NO3 (20ppm), really high Sulphates (30-40ppm). So I make a daily mix of Magnesium Nitrate, Potassium Phosphate. Haven't yet seen a need to add any trace elements based on plant growth. The duckweed is looking good.

Good luck with the hygro!


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## dw1305

Hi all,


> the 'duckweed index' is genius for checking out whether the issue stems from CO2 V mineral deficiency.


That was why I chose a floater, to take CO2 out of the equation. The Duckweed Index is a KISS method for those who aren't interested in aquascaping or an all singing and dancing tank, but just want a planted aquarium with reasonably healthy plants. 

I've converted quite a few people on fish orientated forums to growing plants and using the "Duckweed Index", primarily as a method of improving water quality and tank stability. 

In a lot of cases, often after some initial scepticism, they've found that they can grow plants, it isn't difficult and that actively growing plants are the single most important factor in maintaining water quality. 

Now all I've got to do is to convince every-body that wet and dry trickle filters are also the way forward and  I'll never need to post again.

cheers Darrel


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## Tim Harrison

Sorry to hijack the post somewhat, but I have the same holes developing on the lower and older leaves of some of my stem plants (_Ludwigia repens_...I think), a bunch of which were introduced about 2 weeks ago - new leaves are fine.

I dose 2ml TNC Complete every other day (60l tank) and the plant is in line with the flow from a 750 l/hr Eheim Pro, and since I use an UpAqua atomizer the CO2 as well. The drop checker is the yellow side of lime green pretty much the whole 10hr photoperiod which is provided by 2x15w T8 bulbs.

My question is...

a/ is it likely to be a deficiency in my tank or
b/ is it possible that the plants are suffering from some sort of post traumatic stress syndrome from being kept in      less than ideal conditions in the LFS or
c/ natural partial death as the plant withdraws nutrients from poorly functioning cells (old age) to promote the growth of apical meristems :?: 
d/ None/all/some of the above  :?:


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## miku

Hi all,

thank you very much for help and advices. 
Yesterday I made 50% water change and cut off all damaged leafs. I dosed potassium as usually and I started adding of NO3 and Mg. I made all-in-one solution DIY TPN+ (3) from the James' Planted tank page. I'm going to dose 2ml of this solution daily. Which means that I'm going to add daily about 3ppm NO3, 0.15 PO4, 2ppm K, 0.2ppm Mg.

Regards 
Dusan


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## dw1305

Hi all,


> I dosed potassium as usually and I started adding of NO3 and Mg. I made all-in-one solution DIY TPN+ (3) from the James' Planted tank page. I'm going to dose 2ml of this solution daily. Which means that I'm going to add daily about 3ppm NO3, 0.15 PO4, 2ppm K, 0.2ppm Mg.


 My suspicion would be that that this should do the job. You should see a fairly quick response if it is a nutrient deficiency, as both magnesium and nitrogen are mobile within the plant tissues and the new leaves should green up straight away.

cheers Darrel


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## niru

Hello Moderators:

the previous post (one above mine) by "enjoydiablo3" is a SPAM!! Please check if this is a robot poster??


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## mantozhke

Hi. Could this be the "potassium deficiency" on my pinnatifidas?


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## dw1305

Hi all,





mantozhke said:


> Could this be the "potassium deficiency" on my pinnatifidas?


Looks like it.

Those are the right symptoms, yellowing with pin-holes, and effecting an older leaf.

cheers Darrel


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## ceg4048

Hi,
    I'll have to disagree with Darryl here. Potassium deficiencies are rare and these symptoms would be the right symptoms if this was terrestrial growth.
If these symptoms appeared during submerged growth then it is more likely to be a CO2 issue.

Cheers,


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## alto

Is this established pinnatifida - or recently planted?


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