This plant is really fickle about things. It loves nitrogen and potassium. The pinholes are from a lack of potassium. The leaves falling off are typically due to low light, generally from being shaded. Extra N can help it be more resiliant, and plant tabs can help as well. It's a heavy root feeder.
Some additional advice: Drop the Seachem NPK line and get dry powders from Aquarium Plants, Aquatic Plants, Planted Aquariums, and Aquarium Plant Fertilizer. I know you're not dosing enough, unless you buy in 4L bottles and have a fat wallet. Your CO2 is low (shoot for a pH of 6.2 or 6.0), up your traces to 10mL every other day. This should help with your staghorn and plant issues.
Some additional advice: Drop the Seachem NPK line and get dry powders from Aquarium Plants, Aquatic Plants, Planted Aquariums, and Aquarium Plant Fertilizer. I know you're not dosing enough, unless you buy in 4L bottles and have a fat wallet. Your CO2 is low (shoot for a pH of 6.2 or 6.0), up your traces to 10mL every other day. This should help with your staghorn and plant issues.
