Brown patches probably due to nitrogen shortage

• pH:
• Temp:
• KH:
• GH:
• NH4:
• NO2:
• NO3:
• PO4:
• Iron:
• Dosing: 25 ml Excel, 15 ppm NO3, 2.5 ppm PO4, 1 tsp MgSO4, 2 tsp CaSO4
• NO3:PO4 Cumulative Dosing Ratio: 15:2.4 = 6.25

Notes:
The angelfish fry weren't growing as fast as I liked, so I released them into the main tank, where I hope they'll hurry up and get large enough for me to get rid of them to a local fish store. With all the extra fish, it's becoming harder to keep the green alge from growing. The angelfish pair laid eggs yesterday.

During the water change, I noticed that there were black patches on the leaves of the java fern, so it seems like there was a shortage of nitrogen, rather than potassium, and that also caused the brown patches in the stargrass and baby tears. Unfortunately, I didn't bother to measure the nitrates this week to verify this is the case. I tore out the stargrass and replanted the green cuttings. On the other hand, the R. indica seems to enjoy the lower nitrate levels and grew quickly this week.

50% water change:
20 mL Amquel+
2.5 tsp baking soda
1 tsp MgSO4
2 tsp CaSO4
15 ppm NO3
2.4 ppm PO4
25 mL Excel

Cleaned AquaClear filter today.