I got frustratedd and pulled everything apart.
I found a black sludge covering everything so I cleaned with salt water and let it dry before I put water back in.
I did add another filter to the smaller pond and plan to run them seperate to see how it goes.
My fish will stay in the 300 gals for a while, they are doing well and even the fish that was in distress is eating and looking much better.
I am planning to re-introduce the plants in first to see how that goes before putting the fish back.
I shortened the return hose from the filter so it is splashing and when I filled the pond I let the water splash and so far no bubbles, I am going to introduce the plants first and let it run to see if the adittional filter helps.
Thanks for all of your advise.
I was so stressed.
