Ratio of K/Ca/Mg in Equilibrium and stunting

• pH:
• Temp: 77
• KH:
• GH: 7
• NH4:
• NO2:
• NO3: 10
• PO4: 0.75 (before dose)
• Iron:
• Dosing: 5 mL Flourish, 0.5 ppm iron chelate, 1.0 ppm KH2PO4
• NO3:PO4 Cumulative Dosing Ratio: 10:2.8 = 3.6

Notes:
A lot of the stem plants are still growing in stunted, and I strongly think that it is related to the ratios of K/Ca/Mg. Although Equilibrium is convenient, I am frustrated with being unable to change the ratio of K/Ca/Mg. I ordered some Calcium Chloride, Magnesium Sulfate, and Potassium Sulfate from www.gregwatson.com so I can fiddle with the ratios. Specifically, after looking at my previous blog entries, my theory is that the amount of K being dosed by Equilibrium is too high, relative to the amount of Ca and Mg being added.

One of the stunted Rotala indica

The reason why I think this is that I looked through my weekly tank pictures and corresponding blog entries, and during the period of the biggest and lushest growth, I was in a situation in which I was slowly trying to lower the GH from about 8-9 to 5-6 by adding less Equilibrium (3 tsp) during each each water change. What that means is that for that period of a couple weeks, the GH level was higher relative to the amount of of potassium being added, at least until the GH lowered to the target range and equalized back to the ratios being added by Equilibrium. During that time, there was also a slight deficiency in potassium (stargrass is good indicator of potassium deficiency). 3 tsp of Equilibrium adds approx 15-16 ppm potassium in my tank.

Also, I've read that potassium aids in the uptake of iron, and during that period of time, I was having difficulty with iron deficiency (pale stargrass leaves), even though I was dosing up to 2 ppm of iron chelate daily! Currently, I have no problems dosing only 0.5 ppm iron chelate daily or even less. That could make sense if there was also a deficiency of potassium during that time, and plenty of potassium now.

Another possible idea I've been thinking about is that perhaps at higher GH levels, the plants become more forgiving of much higher levels of potassium, meaning at or above a concentration threshold of Ca/Mg, plants will still uptake Ca/Mg in sufficient levels even if there is an excess of potassium. What could be this higher GH level in which the Equilibrium ratios of K/Ca/Mg would be okay? I currently have the GH at 7. Maybe 8-10, I don't know. Another possible view on the same idea is that with higher potassium levels, plants uptake more potassium and also need higher quantities of Ca/Mg.

I want to try cutting down on potassium first, though. If cutting down on potassium results in fixing the Ca deficiency, but causes a potassium deficiency, then I will try this second method of raising both potassium and GH levels together. As soon as I receive the chemicals, I will put these theories to the test.

Related post in a forum.