Backyard Aquaponics
A place to discuss aquaponics

+ 1

Overstocked, I would probably only have the SP in that sized tank.

At a minimum I would keep pumping during the night to increase water turn over until you can dispose of some of the fish

Trust me, I learnt the hard way, my expanded system will have a FT volume of 7,500L and I will only be stocking 50 trout and 50 SP.

It sounds like you've plenty of aeration with the air-stones and the auxiliary pump, but adding O2 to the water is only half the issue with keeping fish healthy and happy, particularly trout.

During the night, the fish are still generating waste and ammonia and for nearly 1/2 of a day you're not filtering this out or allowing the bacteria exposure to do their work and convert these "nasties" to nitrates for the plants?!

Under your current pumping regime, do a complete water test first thing in the morning after the pump has not been running for nearly ten hours, then, switch on the pump and leave it running continuously for a few days and then do another water test. In theory*, they should be chalk and cheese. Should you establish that you weren't pumping enough, you can trial timed sessions for the whole day and night, you might find that 15/45 still works when you do it every hour.

If pump noise is an issue, instead of switching off the pump, sound insulate it as best you can.


Scott

* The difference between "theory" and "practice"? In theory there isn't any difference, in practice there is!