I may have missed too much of your pond saga to be helpful, but how often are you cleaning pond? Not a prof, but think cleaning should be rare. Buy snails, tadpoles, algae plants to clean? Ponds like their eco-system.
“pond guy said I dont have enough fish to put territory pressure”
hmmm... my pond is much smaller than yours. That alone may disqualify me of being any help to you on pond matters.
“Territory pressure” is definitely NOT my problem. Is pond guy saying buy snakes to threaten blue heron and other predators? May be a good question to ask him: Approx how many fish in your pond WOULD exact “territory pressure”?
It can hold 30 fish he says and I only have 5 so territory shouldn't have been a factor for the presumably other babies getting eaten by the other fish. Snakes are bad because they will eat fish if they can, I had 7 good sized frogs when we cleaned at the beginning of spring and we found only 1 in this cleaning.
As far as cleaning goes we do it every spring. The reason we did it now is because I replaced the filter. We had so much algae on the bottom it ruined the old pool filter. So I installed a real pond filter and it works great.