20g would be challenging to use as a grow out farm. Your space is limited, parameters can change quick.
If you want to end up with coral to trade/sell, you should go for high value, easy to grow, self multiplying items like zoanthids and shrooms.
I have done this several times - buy a high dollar Zoa. Higher the better. Let it multiply. Separate onto individual plugs. Repeat. Let a few plugs get 2-3. See what you can sell/trade for.
My exosphere colony has paid for its initial investment 10x in a year. I went from 5 to 50+. I frag 5p and sell for 50$. The colony regrows it. Even though the price has come down over the last year, it’s all profit, no matter what I sell for, because I grow them for free.
I stepped up to higher dollar designer zoas. 200 and 300 a polyp.
In a few months I went from 1 to 6 and from 1 to 4. I take half off what they go for online. 500$ invested. Turned into $2400 in zoas in a few months. Zero work essentially. At the time, I had 10 combined, sold 3, and that paid for the initial investment. Everyone after that, is pure profit.
So hypothetically let’s say you settle on one coral, it doesn’t matter what. Something fraggable. And let’s say you have space for 20 plugs. Would you want 20 frags of a coral worth 25$? Or 20 plugs of a coral worth $100 or 200$?
Just something to consider
torches and hammers are great but slow growers. You can have a torch for up to a year before it splits. I suggest a high end one. Why wait a year to turn one 75$ torch into two? You could turn a 300$ torch into two
