Thoughts on stunting

• pH: 6.6
• Temp:
• KH: 5
• GH:
• NH4:
• NO2:
• NO3: 5 before morning dose
• PO4:
• Iron:
• Dosing: 15 ppm NO3 morning, 1.8 ppm PO4 morning, 5 ml Flourish, 20 ml Excel
• NO3:PO4 Cumulative Dosing Ratio:

Notes:
The rotala doesn't grow in stunted, but I'm curious as to what changed to stop the stunting. It seems to be related to some ratio/amount of K/Ca/Mg. Right now, I'm pretty happy with the ratio of Ca:Mg of 3:1 (10.4 ppm Ca, 1.25 Mg added during 25 gallon water change). I'm still trying to figure out the optimal value of K, though (e.g. whether K dosing from just the KNO3 and KH2PO4 is sufficient, or is more needed).

Also, there is still a little bit of brown patches still occurring in the stargrass, even though I've been monitoring the nitrates pretty closely. I wonder if it could be a deficiency in potassium? I dosed plenty of nitrates today. I'll watch the plants another couple days to see if there are more brown patches developing before I try to add potassium.