WEEK 7: Potassium deficiency?

• pH: 6.7 morning
• Temp: 74-75
• KH:
• GH: 6 (before dose)
• NH4:
• NO2:
• NO3: 0 (before dose)
• PO4: 1.0
• Iron:
• Dosing: 5 mL Flourish, 20 mL iron chelate (2 ppm), 40 mL KNO3 (8 ppm), 3 tsp Equilibrium

Notes:
I lowered the CO2 bubble rate a little bit (1.9 bubbles/sec to 1.7 bubbles/sec).

I've been thinking (again) about the pale leaves and black patches on the stargrass. Ive read that a potassium deficiency can also cause iron chlorosis. I've been adding 3 tsp Equilibrium, which adds approx 14 ppm potassium to my tank. Dosing KNO3 also adds potassium. For each ppm of nitrates, approx 0.65 ppm of potassium is also added. I've been steadily lowering the GH to get it to my target of 6, but I think I will add 3 tsp more of Equilibrium to raise the potassium provided by Equilibrium to approx 35 ppm.