I know what you mean. When I first got into fluid beds I was turning everything that would hold water into one, as well as trying out all sorts of fluidizing gizmos including experimenting with different types of lawn sprinklers and spray heads. I must have built at least 50-60 different styles and types of fluidbed traps including one out of an old mailbox.
Found out it's hard to build one that wont recover gold. It's shooting for perfection that makes it challenging.
For $2.98 at Lowes This works pretty good in the bottom of a bucket (face the spray down of course) I experimented drilling holes in the inside edge and outside edge too. Turns a bucket of sand into quicksand.
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Had the idea of running several of them sideways in a large tube style trap but never tried it out...........
Might even work in a gold pan with a bilge pump attached to convert into a fluid bed gold pan. (panzooka)
GG~