# potassium defieciency



## Mr P (15 Feb 2012)

hi every one,i am EL dosing my tank,i am using James C recipe,i have holes in leaves,distorted growth,yellowing of leaves,stunted growth,it is very noticeable on the sword plants,i have been on the planted tank and it appears i may have potassium defieciency,what potassium do i need to increase,potassium nitratre or potassium phosphate? i am using the EL starter pack ,any help would be great.  ,skankypup.


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## Dan Crawford (15 Feb 2012)

Hi, I would suggest that it's not a potassium deficiency and it's more likely a CO2 deficiency. Could you please give us some more tank stats ie, filter, tank size, lighting, photoperiod, substrate, CO2 method and bubbles per second?

Cheers


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## ceg4048 (15 Feb 2012)

Hello,
       Your problem is poor CO2 or poor flow or poor distribution. If you are dosing EI levels of nutrients you should not see these deficiencies, so the conbination of observed nutrient defficiency (yellowing) and poor CO2 (holes and distortion) points to poor flow/distribution.

Cheers,


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## Mr P (15 Feb 2012)

thanks for your feedback,my tank stats are,175litres,filter is rated at 1100 litres per hour,i have eco -complete substrate,i am using a swan neck outlet on the filter,i am using pressurised co2,about 4 bubbles per second,i do have a koralia 1600 powerhead which is off at the moment as i was try to fight a BBA outbreak which i seem to be beating at the moment,i have 2x24watt T5 lights on for 6hours a day.do you think i need to switch the koralia on again?


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## gmartins (15 Feb 2012)

Hi,

I agree that your case is a clear low/poor co2 level/diffusion thing, so you must address this. However...

On my last scape, as it matured and plant mass grew I started noting some yellowing in staurogyne. All other plants seemed healthy (even crypts). 

I'm also using Jame's recipe which is based only on KNO3 and KH2PO4 and dosing via EI. So levels of K are a bit low when considering the suggested "optimal" 20-30 ppm. I hence decided to add a bit of K (via Elos K40) and in two weeks stauro was green again. From that time onwards I used to dose KNO3 and KH2PO4 as before (3x per week) but included a bit of K40 once a week after wc. This seemed to do the trick.

So I suppose that basing EI on KNO3 and KH2PO4 alone is generally ok but, in a few circunstances (large plant mass, lots of CO2 hence lots of demand), there may be some slight shortage of K... Just my experience though.

GM


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## plantbrain (15 Feb 2012)

In order to induce on purpose..a K+ deficiency.....you'd need to drop below say 2-5ppm + or less.........

I do not think that is possible with most KNO3/Kh2PO4 dosing schemes.


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## gmartins (15 Feb 2012)

My point exactely!

According to James' recipe:

33 g of KNO3
7.2 g of KH2PO4
mixed in 250 ml of H2O

Suggested dose: 5ml for every 50L

My tank (10L):
1ml 3x/week which equates to ~6ppm per dose.

So I suppose  that the day after dosing my levels of K will be lower than the 5 ppm.

Am I missing anything?


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## ceg4048 (15 Feb 2012)

K+ shortages does not typically show up as yellowing. That's usually an N or Fe or Mg/Mn issue. Did you really pay £40 for a bottle of ferts? I mean, if you wanted more K couldn't you have just added more KNO3, which is 40% by weight in K??? In any case since we don't really know what's in this K40 there is a possiblility at least, that it contains other macronutrients or micronutrients, and that those would have been responsible for the improvement. If you wanted to vefify that it was a K deficiency you would have to use a K salt alone that would not have any other components whose deficiencies are not implicated in chlorosis, such as KCl or KCO3. They don't really say how they derive their K, and they don't list their ingredients, which always makes me suspicious.

Also, it is not necessarily so that just because you add 6ppm on day one that all 6ppm get used up by day two. Uptake rates depend on a lot of things such as PAR, CO2 and so forth.

Cheers,


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## Mr P (15 Feb 2012)

i think that most of the problems i have been having are CO2,flow,i have had nice movement  throughout the whole tank,the co2 is going through a glass diffuser directly under the filter inlet,i am trying to remove as much of the BBA manually and i am spot dosing liquid carbon,i will up the co2 rate some more,i sart the gas 2hours before lightson and leave it on till 1hour before lights off.i thanks again.skankypup.


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## gmartins (16 Feb 2012)

ceg4048 said:
			
		

> K+ shortages does not typically show up as yellowing. That's usually an N or Fe or Mg/Mn issue.



I believe you. I find those schematic diagrams with plant symptoms of nutrient shortages very ambiguous. I just though it were K+ cause I know all the remaining are dosed in excess. Only K could be in shortage as explained in the post above.



			
				ceg4048 said:
			
		

> Also, it is not necessarily so that just because you add 6ppm on day one that all 6ppm get used up by day two. Uptake rates depend on a lot of things such as PAR, CO2 and so forth.



Very true and I do not know my consumption rates cause I haven't make any test yet    However I do know that I have lots of CO2, very good distribution and moderate light so I assume that I have moderate consumption rates and again, lost of plant mass. It's just that K+ is the only one that is closest to its lower boundary level (according to EI).



			
				ceg4048 said:
			
		

> Did you really pay £40 for a bottle of ferts? I mean, if you wanted more K couldn't you have just added more KNO3, which is 40% by weight in K??? In any case since we don't really know what's in this K40 there is a possiblility at least, that it contains other macronutrients or micronutrients, and that those would have been responsible for the improvement. If you wanted to vefify that it was a K deficiency you would have to use a K salt alone that would not have any other components whose deficiencies are not implicated in chlorosis, such as KCl or KCO3. They don't really say how they derive their K, and they don't list their ingredients, which always makes me suspicious.



I did not   . I was given by Felipe Oliveira (FAAO) after a workshop I attended. Never had used it before cause I use dry salts.   

I know I could just up my dose, but I was suspicious it could be a shortage of K+ and so added the K40 from Elos. Otherwise I would be mixing NO3 and PO4 as well (cause I' using a liquid mixture) and would never be able to distinguish whether it was a K+ shortage, NO3 shortage or whatever... 

You're right. They do not give us the composition. But I assume that at least K+ is the main thing in this K40 from Elos. It was the closest I could use without the need to buy more dry salts (e.g. KCL).

Anyways, this is my experience. I know what I did was not scientifically sound (I know belive me, I'm an experimental  marine ecologist). But given that: (i) Jame's recipe is generally low in K+ and, (ii) since adding K40 (even with all the doubts about its composition) plants improved in colour -  there is anecdotal evidence that it was, in fact, a shortage K+, IMO.

Going back to the topic (sorry for hijacking your post skankypup), I thinkg that you are in the right path by raising you CO2 levels, starting CO2 injection earlier and by spot-dosing liquid carbon (careful for not burning the leaves). IME, BBA can be very persistent after installed so cutting off the infected leaves may also be an option. Allow 2-3 weeks for any effects to take place. After this time, assess what has improved and what can still be improved.

cheers,

GM


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## Mr P (16 Feb 2012)

I have been testing my PH levels today starting 2hours before lights on,turned on the co2 and checked the PH levels every 2hours as suggested by ceg on another post,i now now that the co2 levels are not up where they should be at lights on,i will start the gas an hour earlier tommorow,the overall levels needed increasing a bit as well.hopefully this will now sort out the problems many thanks again,skankypup.


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