New toilet....loose tank

Hi.
Just installed a new toilet in my boys' bathroom. Followed all directions. Seems to be fine, but the tank is not "tight". It wobbles quite a bit. Rechecked my work - not sure where or what I did wrong. Suggestions?

It sounds like you have not tightened the tank completely. You should tighten one side until it is starting to get snug, then go to the other side and tighten it down. Alternate from side to side until both bolts are snug. At this point, the tank should be touching or almost touching the bowl.

Assuming the tank now sits evenly...as Gary said, tighten each side alternately a little bit until it is close to touching the bowl. I like to put a piece of paper underneath the tank and stop when I can just withdraw it without tearing or much resistance. The minuscule gap allows for a little expansion. You can stop before you get it that tight if you want. As long as you do this evenly, you should not break the tank unless it is already defective.

Is there space between the toilet tank and the wall? If so how much space? If its a small space and the toielt tank is tight but still moves,you can use a piece of foam insualtion to slip between the wall and the toilet tank. If this was not a new toilet we are talking about I would consider you had the wrong tank to bowl gasket but you say the toilets new. If you have a full 2" between the tank and the wall consider installing a 14" toilet or installing a 3 bolt tank style toilet. You may just need to tighten it more as others have suggested,just becareful. You need alittle movement for exspansion and contraction but not much.

What is the brand and model of the toilet?
Some designs are designed to have wobbly tanks...