Backyard Aquaponics
A place to discuss aquaponics

Hi,
I started a small new indoor system, 210 L drum cut in half in the length, growbed on top with fishtank below, I’m pumping water from the fish tank through a filter overflowing into the grow bed, i have a external suphon back into the fish tank, 7min to fill and 6min to drain, dual air pump with ball and disc for air.
I added half the tanks water with cycled water from another system and half fresh water, PH is 7.2 temp is 20deg c, the tank is open at the top, i added 10 x 4cm Talapia to the tank, within 4 hrs all but one had jumped out of the tank and onto the floor.
What do you think could be the cause of this behaviour?

Tilapia jump, especially when stressed. In a system with no sump tank, the water level changes significantly and that stresses the fish. For sure put a net or lid of some kind on the tank. A better design would be to use a whole barrel laid on its side for the fish tank with an opening cut in the top. This will allow more water for the fish and a smaller opening. Maybe if they don't lose half the water every 10 minutes, they will be less likely to jump.

Thanks for info shared