Ok so I am working with my first AP system.
275 gal IBC as fish tank.
2' X 4' X 12" (11" media) times 2 Grow Beds.
2' X 4' X 10" (10" media) single bed.
4 air bubblers in fish tank.
10 constant flow terrace bucket system. (bucket half full of clay pebs, water falls in top washes pebbles exits bucket thru bottom, No Standing water ((not nft or raft))).
So I tried to use Murry's technique of adding water MaxiCrop 1 qt into 250 gallons and added plants.
Waited two weeks and introduced 1 catfish 2 red ear perch.
Cycling tested via API Master Freshwater, showed cycling as expected, all be it slower than expected. Water was at about 60F. Ammonia showed then subsided to the nitrite. Had an algae boom as spring started. Nitrite climb into 5ppm. One perch died. Stopped feeding and nitrite subside to nothing but no nitrate readings. (I have plants in system) Elected to add 25 small Tilapia hoping to bring my system to about 1/2 fish capacity (but fingerlings).
Now it is two weeks after adding Tilapia and I have no readings of anything (other than ph 7.2). However the fish feed almost entirely on the Algae that grows sparingly on the inside of the IBC. I cant measure intake or weight gain. Visually they appear to have put on no mass. They will not eat and half lie lethargically at the bottom of the tank while the other smaller ones stay very near the surface. The ones at the surface might be gulping air, not real obvious though seems if the just like to hang there. (have air in tank) Several fish appear to be Dying with a single Tilapia dead.
Known system possible problems.
Close to not being able to turn over 275 gallons in an hour. (600 gallon pump running two 15 minute intervals per hour.)
55 gallon sump barrel has lots of clay and general gunk in it from System (looks expected, broken clay ball, red sand etc.)
BLUE unidentified pool liner, lining the grow beds.
Tried multiple types of food to encourage fish to eat. (Excess removed*, what I could)
Any ideas or encouraging words?
I guess it is OK to not see the Nitrate if the plants are eating them but I fear something else is amiss. Since test are good I am leaning towards bacteria if it is a problem I can do something about. Just hesitant on salting the tank as I feel now I am blindly guessing at problems and throwing a solution at it that might be multiplying the problems.
Thanks in Advance
I would question aeration. Temp was border line for tilapia.
How did you make out ?