Backyard Aquaponics
A place to discuss aquaponics

My husband is planning to build a greenhouse for cold weather crops. He is going to use a combination of an NFT system and Food and Drain beds. The NFT system will consist of its own pump, and it will be 128 feet of 2-inch PVC, 128 feet of 4-inch PVC, and 112 feet of 6-inch PVC. The flood beds will be 4 beds that are 3x16, 3 feet deep, and are fed by another pump that is split between each bed. The media will be pea gravel. My husband has plenty of experience in plumbing, electrical and construction. And we have done hydroponics before but want to try aquaponics. He has a system laid out that he believes will be very efficient.

However, the only part he has questions about is the pond. What size pond and how many fish are needed to create the proper bioload for this system. And is better to have two ponds or one large one? He will be using bluegill fish that we plan to harvest when they reach full size. They are hardy for colder weather and are native here in Missouri. We need to take into consideration that every so often the fish will be harvested to be eaten and that this may reduce the bioload. He is also set on putting this pond/s in the ground to help keep the temperature stable.

Also, a bit off topic, but has anyone had experience in the Food and Drain System being outside of a greenhouse where it rains a lot? If he decided to expand this system during the summer he would like to not have to build another greenhouse. He is wondering what heavy downpours would do to the system. And what would be needed to avoid any potential problems?

Correction: The beds will be 1 foot deep, the pond is what would be 3 feet deep.

Personally I'd split it into a couple of different systems/tanks, a couple of 5000L tanks would suit quite well I'd think.