10- 20 Gallon Aquariums
+/- 1/8 tsp KN03 (N) 3x a week
+/- 1/32 tsp KH2P04 (P) 3x a week
+/- 1/32 tsp (2ml) Trace Elements 3x a week
50% weekly water change
Although I don't do the 50% water change. Tried it and didn't notice any difference in fish/shrimp/plant behavior.
It's a good starting point and you can adjust the dosage as you see fit. I prefer to dose the trace elements twice a week rather than three times. Seems to keep the hair algae at bay. Although I could be very, very wrong but it's just my personal experience.
Tank has 36w of PC lighting with DIY CO2.
I just take a used yogurt cup and fill it with water, add ferts, mix, and pour into the tank. If you have good circulation there should be no worry about spreading the ferts out.