Hello and I am purchasing a soft shell and had a few questions.

I have a decent amount of sand and a few pieces of wood. But it used to be a fish tank so its not designed for a turtle so the water has to be rather high, but I made it just low enough so the filter would still work. But I have heard if I keep the water temperature a proper level the soft shells dont often back. IS this true? Also are florida soft shells meant ONLY for brackish tanks? it seems they only require like a tbsn every gallon. Would that be enough salt to kill my pleco? And if you think the water level is too high and the baby soft shelll wont handle it what species do you think would be better? it is a 60 gallon fish tank. By the way I will still add a dock and UV lamp even when the water temp is the proper level it will just a be a bit higher for him to reach. Also I will only have one soft shel and a few fish .

Any tips and help appreciated.
-Keith