Getting 2 new fishes today.

[Catpicklesdog]

I thought once they eat other stuff, you are home safe...this is tough. I am setting up a 75G (90#LR) with 20G refum to get a mandarin. What else can I do to make sure there will be enough pods? (can't afford weekly pod bottle.)

You're on the right track. You have a large enough tank with enough rock to help sustain the pod population. I don't know how old your tank is, but if you leave it at least 6 months preferably 12, add a bottle of pods once a month (half in the tank, half in the fuge) then you're on your way. I have a bonus (I always look on the bright side) that I also have flatworms which my mandarin eats (this tends to apply only to the spotted mandarins).

HTH