You don`t have to have a tumbler. Just put an air stone near the eggs to create a current over them. I always used methyleen blue (not sure about the spelling) to retard fugal growth. I`ve hatched many thousands of cichlid eggs that way. Good luck.
Oh ok thanks ill do that then. I got one of those super luft pumps and a bunch of air stones and a 27 gallon rectangular tub i was going to do it in so ill just try your idea this time then, thanks for the advice. I was thinking about it but wasnt sure how effective it would be.