I would wait for someone who may have more experience with mortar (I have none, but have read about people using it and watched videos). If you are worried and don't want to wait you could continue and seal it. Get the tank setup and let it run for 30days without frogs in it. See how it holds up. If it starts cracking a lot you can then make the decision to break it down and start over. You've made the first move in starting a thread on this site. Keep posting your updates or questions. There are several very knowledgable people on this site that can lend their advice or tips to help you along the way