# The more potassium the paler the plants



## kekon (Aug 1, 2005)

I have really frustrating problem. Whenever there is more that 10 ppm K+ in the water column the tops of plants get pale, yellow and light-pink in the case of red plants. Obviously they grow much slower as well. I had the same problem 2 years ago i was unable to solve it. I gave up and removed the tank for a year... Now i returned to the hobby and set up new tank. The problem appeared again. When i descrease potassium doses the plants get normal vivid colors. However, they cannot grow faster because of too low potassium. When i add 5..10 ppm of K, they get pale and yellow. It resembles iron deficiency but in case of iron deficiency leaves are not uniformly yellow (some parts of leaves are yellow but some are not). In my tank young leaves become uniformly yellow.
I must say that this is NOT caused by too low N, P, CO2 etc. I added more and more P and N but it didn't help. (too much N caused stunted tips).
I also added much micros but without effect. When i add quite high manganese dose (0.2..0.3 ppm) some plants get orange colors. I also experimented with single micros (boron, zinc, molybdenum) but it failed to work either. Of course high iron doses were added (0.5 ppm Fe didrectly to the tank)
Did anyone of you have similar problem ?


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## yildirim (Nov 25, 2004)

In some cases I have seen that excess K caused Mg deficiency which also causes pale and yellowish coloring. But the amounts were much higher than 10ppm. In your case, I do not know if you can be sure, but the problem is perhaps K was always the limiting factor and when you increase it the limiting nutrient may switch to another one.


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## kekon (Aug 1, 2005)

I added magnesium but without effect. I know many add much K but they don't have the problem described.


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## yildirim (Nov 25, 2004)

When I said Mg deficiency I meant that K caused Mg to be used properly. These two are not the same. Adding more Mg will not solve the issue. But I again insist that the problem shouldn't be related to excess K.


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## aquamaniac (Apr 14, 2005)

Hi Kekon, please read this thread, it helped me a lot :

http://www.aquaticplantcentral.com/forumapc/algae/62516-method-controlled-imbalances-gda.html

After 50 % water change try to dose nothing but KNO3 until GSA appears.


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## Avi (Apr 7, 2004)

Whoa!!!! Between the Spanish and the English and the typos and all the abbreviations a guy can get a headache! This link and the ones in it are great reading but really contains an enormous amount of information to consume. Can I ask this: Is what is being said here, that if your plants are growing very well, the colors are great and the only algae in the tank is GSA (green spot algae) then just stop dosing everything but the KNO3 (potassium nitrate) until the GSA disappears?

and....

what do you do about dosing once the GSA disappears.....Start the EI doing again?

THANKS if you can answer that.


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## Cliff Mayes (Jan 29, 2007)

Your comment reminds me of a missionary visit to a Salt Water Workshop meeting. The meeting being run by an MD with a lot of very involved Hobbyists. After listening to a very technical discussion about chemistry from the Chair and members I noticed a new young couple with glassy eyes and I couldnt help thinking that there goes another potential Hobbyist out the door. You do not need a Chemistry degree to keep a tank.

Yeah. There is a lot to learn and soon you will be talking the talk but all of us started out as beginners and the Hobby has changed dramatically in the last few years. Oldtimers, like me, have had to learn all sorts of new stuff while not exactly throwing out all of the old stuff. New technology as changed everything and the younger folk have never known any different but remember that this Hobby does not generate large dollars for anyone so basic research is almost nonexistant. Empirical evidence is about all we have. There are many disputes, based on individual experience, and these will continue for a long time.

The keys to sucess in this Hobby are Water Changes and patience. Money helps but there are many ways of stretching dollars. Lots of folk in and out of the game make for many bargains if you just wait for them.


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## Edouard (Jun 7, 2005)

Hi Kekon,

I have had the same problems you had for the last year or so.
I regularly read your posts, hoping that you have finally found an answer to those "stunted tips, pale new leafs".

I reduced the amount of N as you stated it was responsible of stunted tips.
It worked for me to, until recently, where I have also had problems with pale new leafs.

I can't really find an answer to that, I just wanted you to know that others are also working on that 
Please keep on posting, as your experiments help, and might succeed in the long term.


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## kekon (Aug 1, 2005)

> The keys to sucess in this Hobby are Water Changes and patience. Money helps but there are many ways of stretching dollars


We should add the "patience deficiency" to the plant mineral deficiencies list 
Well, i've just made some new observations. I've just come back from 5-day holiday and i can see improvements on my plants but i have to wait some more time to confirm i'm right. I see much better colors on plants in spite of the fact there was 20 ppm K in the water column (this amount of potassium usually caused problems with chlorosis before)

My tank is:

Capacity: 210 liters
Lighting: max. 0.9W / liter (3 x 36W 5400K tubes and 2 x 36W 6500K tubes)
Substrate: plain gravel (with no additives)
Water: RO only (Ca 20 ppm, Mg 5 ppm, Cl 5 ppm, Na 2 ppm, SO4 40 ppm)

Micro fert:

Fe:	0.074	% (4.1% EDTA + 3.1% DTPA)
Mn:	0.042	% (EDTA + DTPA)
B:	0.0029	% (H3BO3)
Zn:	0.0043	% (EDTA)
Cu:	0.0043	% (EDTA)
Mo:	0.00013	% (ammonium molybdate)
Ni:	0.0003	% (nickel sulfate)

Anyway, this is what i did:
Before the holiday i did 50% water change but didn't add any ferts. I turned on UV lamp because there was bacteria bloom in the tank (the water turned murky) and there was lots of thread algae (Rhizoclonium) (the tank hasn't been cycled yet but it has nothing to do with chlorosis caused by potassium). Also, i did 3-day blackout. After the blackout the water was crystal clear. Again, i did 50% water change and added 20 ppm K from K2SO4 to the 50% of water changed. Two 50% water changes and UV light virtually removed all the micronutrients from the water column.
I also added about 34ml of my micro fert (which composition is shown above), 0.5 ppm PO4 and 2 ppm NO3, 0.66 ppm urea, 0.2 ppm NH4 (these 3 forms of nitrogen come from "Eudrakon N" fert which contains urea, KNO3 and NH4NO3). 
Now, when i'm back home after 5 day holiday i see much better colors on my plants and also some rosetting effect on rotala rotundifolia and some deformed leaves on Cardamine Lyrata. 
The rosetting effect is probably caused by too low zinc and boron because i added little micro fert. However it is not big problem now. But why the plants got better colors despite low Fe ? 
I don't know exactly yet but i made 2 changes:

- i used 4.1% EDTA + 3.1% DTPA chelator instead of sole DTPA (called Dissolvine D-Fe-11) 11% Fe
- i didn't add potassium sorbate preservative to the micro fert (potassium sorbate is an anti mould 
agent used in food)

So, was it for the change of chelator that helped or elimination of potassium sorbate ? Is it possible that changing iron chelator from "Dissolvine D-Fe-11" to "4.1% EDTA + 3.1% DTPA" improved colors on plants ? Or perhaps potassium sorbate i used is harmful to plants ? 
The only way to check this is to continute using the micro fert with "4.1% EDTA + 3.1% DTPA" Fe chelator but without potassium sorbate (also 20 ppm K will be kept). If it helps i will add potassium sorbate. If after the addition the plants get chlorosis again it will mean potassium sorbate is harmful to plants. If not, the "Dissolvine D-Fe-11" chelator will be suspected as the cause of chlorosis. 
It may sound strange that "Dissolvine D-Fe-11" chelator may cause chlorosis but i noticed its solubility is much worse that that of 4.1% EDTA + 3.1% DTPA. In order to dissolve it i have to use hot water.
Anyway i will keep on observing what happens in my tank after all those changes i made.


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