Old freshwater to saltwater?
My dad just bought a geocube tank and it's looking fantastic, with little things coming out of the live rock he got and something new everyday he says, exactly what I wanted for my sons room. He has a freshwater aquarium in there now, but it's kind of boring, same old fish and not much else going on, which was why I wasn't upset when the live plants I planted in there came with snails lol.
I was wondering though, what the cost would be to turn a 20g freshwater to a small saltwater tank? Mostly just coral, maybe one or two fish, but the biggest thing I wanted was the little live stuff for his tank, the new stuff in the sand and whatnot. This possible for less than the cost of just a new cube and starting from scratch?