# High potassium but low magnesium



## jonathanj (18 Aug 2018)

Did a test on my low tech tank last night and tested the potassium and magnesium for 1st time as did have little trouble with few crypts with odd leaf getting yellow with tiny black/green pepper specs all over leaf  and melt

the readings was

potassium around 18mg/l    was off scale on jbl  test kit
magnesium  2 mg/l  

are these way out and need putting right for health of plants and fish


----------



## Zeus. (18 Aug 2018)

Well most folk don't test as the results can be hit and miss. I have never tested the ferts levels in my tanks. Just use EI dosing and dose to levels which plants seem happy with with weekly 50% WC to reset tank.



jonathanj said:


> odd leaf getting yellow with tiny black/green pepper specs all over leaf and melt



Sounds like to much light with poor CO2 implementation with inadequate flow also!


----------



## jonathanj (18 Aug 2018)

Zeus. said:


> Well most folk don't test as the results can be hit and miss. I have never tested the ferts levels in my tanks. Just use EI dosing and dose to levels which plants seem happy with with weekly 50% WC to reset tank.
> 
> 
> 
> Sounds like to much light with poor CO2 implementation with inadequate flow also!


Hi  zeus   and will low mag and high potassium do damage to livestock though  and  I  dose the recommended EI  on my size tank 230gal   works out 175ml  3x macro/3x micro and leave sat and do 50 percent WC sunday     is it the EI  that is giving high potassium as doing whot says on packet


----------



## Zeus. (18 Aug 2018)

jonathanj said:


> will low mag and high potassium do damage to livestock



Low no, But if the K is high it could do OFC

I use TNC calculator to work the stock solution out, but it doesnt do Mg so I use ppm Calulator so last time I was making 3.6litres so just entered the Tank size dose ppm etc and they do the rest giving you the ppm per dose or week

My EI dose per week is





Or I should says double that as I am dosing EI 200% ATM so K 72ppm or 72mg/l

the Mg dose is



per 100ml I dose 200ml x3 a week so 19.7ppm or 19.7mg/l

But these are just an Estimate OFC

So if your K level is high mine must be  my fish/shrimp are fine IMO


----------



## jonathanj (19 Aug 2018)

that does make my head spin all those high tech graphs zeus  

probley wy people try not to get so much into testing water lol


----------



## rebel (25 Sep 2018)

Don't bother with the high K but make sure you plenty of Mg. Remember that a 50% water change will halve your levels in general.


----------



## KeeperOfASilentWorld (2 Oct 2018)

Quoting BarrReport article: "Magnesium’s Role In Aquatic Macrophyte Nutrition":

"While K+ has been discussed as a Mg+ blocker in chloroplast, we should also consider the relationship between leaf K+ and leaf magnesium because as K+ becomes more available, leaf magnesium concentrations for optimal growth increase. In general, ratios of about 4:1 ( K : Mg ) or greater are often associated with the appearance of Mg deficiency symptoms. Satisfactory ratios of Ca : Mg on an equivalent basis may range from 1:1 to 20:1, provided that adequate Mg is present."

"With adequate Mg+ in the medium, even though Mg+ concentration in the plant falls with increasing rate of K+ application, it can stay above the critical level."

"Most aquatic references point to a ratio of 3:1 to 4:1, Ca : Mg. The need for this ideal ratio has never been verified by various research efforts. Therefore, as fertilizer recommendations are developed, emphasis should be placed on providing adequate amounts of magnesium in soil and water rather than the maintenance of a ratio."


----------

