We have a 300 gal pond in which we keep 3 res and 5 koi fish. One of the turtles has decided thst he doesn't like one of the other turtles, so we have to separate them. We have a plastic stock tank which would be perfect but we used it to soak paint off something metal. What was in it was oxalic acid mixed with water. If it is thoroughly cleaned out eould it be safe to put thevtuthe turtle in temporarily?