Hi,

I am located in the south of India in Cochin. I have a 600 lt concrete tank with about 5o tilapia of different sizes. A pump works every 15 minutes to circulate water into a grow bed and to a 100mm dia pipe which is a NFT bed. Water in maintained at a pH between 6.8 to 7.3 and has a tendency to go alkaline very frequently. I manage pH with orthophosphoric acid. 

Fish thrive very well. I feed them with a home made food which is a mix of azzola, hen's eggs and…