The term "tank" is usually applied to the part of the toilet above and behind the toilet bowl and hold the water for the next flush. If I read your comments correctly, you are saying the toilet base (bowl) did not set level. This could be the result of an uneven or non-level floor causing the flange to be not level, it also could be the toilet was not seated properly in the wax ring. If the flange is level and flush on the floor, the toilet should set the same way. If this is not the case, then the proper procedure is to shim the toilet as needed to give it support where it does not contact the floor. The flange bolts do not have to be torqued down with a huge wrench, just snugged down to hold the toilet in position and to keep it from rocking. Caulking is done after the toilet is set and bolted down. It is not to support the toilet, just to cover gaps left by shimming and to keep water from getting under the toilet. (It's not to keep water from getting out from under the toilet) Some local inspectors require caulking all the way around, others want the back section left uncaulked. It sounds like you did things a bit out of order, but if the toilet is setting level and is solid, it should be just fine.