Eggs with no shells can be caused by a few issues other than not enough calcium.
Bacterial or viral infections within the birds body can cause thin, mis-shapen and shelless eggs. The balance between phosphorus, magnesium and calcium may be wrong because of the feed, or the bird is unable to properly break these things down in her body body, and she is unable to use these nutrients to put the shell on. It can also be a defective shell gland. This shelless egg issue can stem from genetics...her momma laid shelless eggs.
Give the liquid calcium a try, but it wouldn't hurt to add some high potency vitamins/minerals to the water as well a few times a week. Also so extra A,D, and E would help as well.
Good luck!