# POTASSIUM DOSING??



## wellbiz (Aug 6, 2003)

I dose to a certain amount, say in your case 20ppm and then dose to replenish what would be removed in a water change in my case 50%...

Do you follow... Dose initially to 20ppm and then dose what every percentage of water you change to get back to that number.


Jason


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## SCMurphy (Oct 21, 2003)

wellbiz said:


> I dose to a certain amount, say in your case 20ppm and then dose to replenish what would be removed in a water change in my case 50%...
> 
> Do you follow... Dose initially to 20ppm and then dose what every percentage of water you change to get back to that number.
> 
> Jason


Are you dosing to get just the water added to 20 ppm K or to raise the tank to 20 ppm K? How much N are you dosing for, 5 ppm or 10ppm?


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## wellbiz (Aug 6, 2003)

SCMurphy said:


> wellbiz said:
> 
> 
> > I dose to a certain amount, say in your case 20ppm and then dose to replenish what would be removed in a water change in my case 50%...
> ...


To raise the tank as a total back to that amount,20ppm potassium... As for N I dose dry, @1/2tbs but it really depends on what my tank water tests at...I shoot for 10ppm

Jason.


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## SCMurphy (Oct 21, 2003)

Starting with no N, if you shoot for 10 ppm N aren't you ending up with 30 ppm K? Do you dose for P?


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## wellbiz (Aug 6, 2003)

SCMurphy said:


> Starting with no N, if you shoot for 10 ppm N aren't you ending up with 30 ppm K? Do you dose for P?


Not to steal Scubas thread, as I have my own going on this issue, but looking at the math you our correct assuming the variable of how much is being used by the plants...... In MY situation this would be true, but I was just making an example for Scuba to go by assuming he isnt adding any other form of postassium like l am...


Thanks
Jason


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## scuba415 (Apr 23, 2003)

thanks for the info! i don't dose N, i have a planted discus tank and they take care of the N, and i would like to keep it as low as possible anyway, even if it does limit plant growth. my main concern was having enough K around so that as much N is used up as possible. thanks for the input.


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## SCMurphy (Oct 21, 2003)

wellbiz said:


> SCMurphy said:
> 
> 
> > Starting with no N, if you shoot for 10 ppm N aren't you ending up with 30 ppm K? Do you dose for P?
> ...


Sorry I dragged myself back to that thread.  

I think Scuba should test a few times to see how his tank is using the fertilizers and then dose as need after water changes. Since we don't (can't) test K I'd dose to get the K at 10 ppm in the volume of the water changed. It's just too easy to overdose K and the problems it causes are not the same as having an algae bloom from overdosing N or P.


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## mm12463 (Nov 22, 2003)

What problems does too much K cause? Are plants unable to take in other nutrients when there is too much K? I'm still getting the hang of this stuff.


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## SCMurphy (Oct 21, 2003)

People using the fertilizing method that threw in as much K as possible were finding plants showing symptoms of nutrient deficiency. Usually it was a plant like Nesea or Hygrophilia that would have the symptoms of Ca or Mg deficiency. Poor growth in a tank that was growing everything else, small crinkled leaves. Then some people started seeing holes in the leaves. Pinholes in the leaves can be a symptom of K deficiency. 

So it is possible that a combination of Ca and Mg deficiency causes a symptom similar to K deficiency except the leaves would rot away. We were going through the idea of reducing the K levels in a tank that had hygro with another guy on this forum. I think it was GulfCoastAquarian but my mind has grown feeble since I turned 40. I am waiting to hear if reducing the K fixed the problem or if I am just wasting bandwidth. 

He did post an update in another thread after his CO2 ran out so I am waiting to hear from him again.


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