hello new to thees community running aquaponic system for the past 3 years

[nimrod bash]

i guess i should give sum details about the system

my system

volume of water is 1100-1400 liters with abut 20KG of fish

feeding 20-30 g"r of fish food

NH3 NO2 and NO3

r at 0 at all time's

PH is 6.2 to 6.5

(the water source PH is 8)

on top of fish food am adding fe supplement and phosphoric acid