This is my 3rd attempt to introduce fish into my system. I thought I killed the first set which were doing well by adding by accident to much chlorinated water. At that same time I added a float system using a PVC liner and wasn't sure if the liner was the problem after a second set of fish died. At that point I removed the liner, washed out my grow media using expanded clay pellets and filled the system using river water that is used to irrigate the orchards. During all this , the ammonia levels have not been above 0.25ppm and the pH is around 6-9 to 7.1. Nitrites have been very low to so low I don't detect any. Nitrates about 40-60ppm. This last round it appears that some of the bacteria in the grow bed survived the washing and what ever because my added ammonia I added was quickly turned to nitrites and then nitrates with the ammonia disappearing each several days after adding it. So I am watching my 3rd set of goldfish slowing dying off one or two per day. A portion of them feed well and the rest sit on the bottom of the tank not feeling well I guess. pH is 6.9, temp 70 and no ammonia to speak of. The temperature during transfer from the pet store to home did change from 70 degrees to 72.5 in the 15min drive in a warm car. I'm wondering if this caused what I am seeing. Any help would be greatly appreciated. Apart from bleach and starting again, I'm not sure what to do.
So how exactly did you introduce the goldfish to your AP system? Do you know the PH/temps of the system at the pet store? Do you know if the runoff of the source water has any pesticides in it?
I was wondering about the fish health at the store, but as you mention it it makes more sense now. Does Certified Organic mean that no pesticides were used during cultivation? Even trace amounts of pesticides are deadly in a marine environment, in this respect fish are extremely susceptible. And then there is a question of the health of the incoming fish. Even fish with optimal health succumb to transport/new tank shock. Can you get fish from another store, to try?