[APD] high ph values, distorted growth, Ca, K

["pieter cool" <pieter_cool at student.kuleuven.ac.be>]

Hello,

I have been following the threat about high K+ concentrations and Ca uptake and I wanted to add my story to the group.

Some time ago I stopped using RO water to reduce the hardness off my tapwater.  Currently I am using pure tapwater in my tank with a Gh +-20  and Kh +-15. 

I am also seeing distorted growth (which looks like a calcium deficiency) of some plants (echinodorus, ammania, hemianthus, ).  I assume it can't be a Ca deficiency because of the hardness of my tapwater.  I did dose a lot of potassium untill recently.  I followed the method advised by Tom Barr.  Last week I stopped adding the extra amount of K2SO4 after every water change on his advice on this list.  I have more than enough K because my KNO3 dosing is really high (almost no fish in the tank).

I was thinking that I get the distorted growth because a lack of micronutrients.  I do add them but the tracemix I use is self prepared.  I use for example Borax, ZNSO4,..and mix them in the right proportions with demineralised water.  The Iron I use is chelated (FeEDDHA).  The thing is that only Iron is added bounded to a chelate and all the other micronutrients are not.  Furthermore my tapwater is very hard and therefore it is impossible to lower my pH values below 7.  This means that only the Iron will remain accessible for uptake by the plants.  Can this be the reason of the distorted growth and can't it be the solution to the problems some guys think are Ca deficiencies?  

Are commercial trace mixes like TMG also working well with higher ph values than say 7.5?

What is a normal concentration of K+ in tapwater when it is as hard as mine?  What is is's contribution to high Kh and or Gh?

What do you guys think about it?

Thanks
Pieter Cool  
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