If you added salt really slowly, maybe. Into sump. Into net maybe.
But there is crud in salt mix, and it can precipitate, so usually much better to mix in a separate barrel.
You can do it that way, but I would mix outside the display if at all possible. 44 gal Brute garbage cans are pretty cheap and affordable. You’ll want something at least that big for future water hanged anyway.
There’s a lot to unpack in that offer, but I mostly see kindness. I’m still a ways away. The tank is in the yard, the parts haven’t arrived and there’s furniture to be moved. But...I’m crafting a detailed plan