A jar test is always easy to perform.

Here is a link to a discussion.

Pond Boss Thread - including jar test

That will help determine if you have suspended silt, charged clay particles in suspense, or an organic bloom.

I don't know if phytoplankton die out in X days and zooplankton die out in X + Y days for the jar in the dark? The zooplankton might just die out due to short life spans or lack of phytoplankton to consume, but presumably they might be second to die?



A pond that is murky due to suspended sediment is certainly preventing sunlight from reaching the organisms in the water column that make up the critical base of the food chain.

Since you are in Florida, do you have enough run off days due to frequent rains such that your inflow water is muddy? If not, then are there creatures in your pond that keep the sediment stirred up? (Such as carp/koi, bullheads, some other types of trash fish?)

Finally, if it is charged clay particles, then those can stay suspended a LONG time. Read some of the alum threads.



The other option is that you have already achieved the population changes that will start improving your pond. Your current fish have all grown up under stunting conditions with some gaping holes in their food supply. Time may be your most important missing ingredient at this point. I suspect your pond is already headed towards a better balance, just very slowly.

However, I am not an expert on that topic, but we do have some experts on the forum. Have you tried any fish traps to sample your forage populations? That might give you a different answer than your feeding observations? If you collect and post that info, you might get some wise advice.

Do you have any decent spawning areas for your CNBG? They are prolific. Perhaps if you gave them a little help, you could jumpstart your forage production?

Good luck on turning your old pond back into a champ!