Tums for Calcium?

[Melstrange]

Good discussion here. I just wanted to add a couple points. Tums are calcium carbonate (CaCO3) but so are egg shells, oyster shells and limestone. CaCO3. is made up of 40% calcium. It gets broken down during digestion and then reformulated into CaCO3 in the uterus (shell gland).
The bulk of the calcium(Ca) in an egg shell is metabolized from the medullary bone in the skeleton of the hen. That then is replaced by Ca in the diet. But plasmatic calcium turnover is extremely fast during eggshell formation, meaning a laying hen's ability to rapidly absorb calcium in all intestinal segments is faster than virtually any other animal instantly supplying the blood stream with the calcium necessary to provide the uterus with needed calcium.
For more detailed information and an interesting read, I refer to this scientific article: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2009000100007

As Mary said, the large particle calcium like crushed oyster shell stays in the upper digestive tract longer than the minute particle in feed and makes it available to the bloodstream during the night when the egg is normally in the shell gland. It has been noted that layers often pick up the oyster shell when the egg enters the shell gland which often happens in the late afternoon. This is because the laying cycle is normally at least 25 hours. For this reason, the bulk of eggs are laid in the morning until the lay cycle catches up to a 24 hour clock and then the eggs begin to come later each day till the hen skips a day, holding the egg that would normally come at night till the next morning.
http://www.nutrecocanada.com/docs/s...-formation-and-eggshell-quality-in-layers.pdf

So to answer the original question, the calcium carbonate from Tums in water would be in solution and some may pass right through the digestive tract without absorption. Further, one wouldn't be able to assess how much the hens are getting.

It is important to note here that there are other things than simply calcium intake that affect shell quality. Most importantly, the ratio of calcium to phosphorus as well as the availability of vitamin D3, magnesium and manganese.
http://www.thepoultrysite.com/articles/1003/factors-influencing-shell-quality/
http://edis.ifas.ufl.edu/vm013

As for tomatoes, the splitting is a result of soil drying out and then after a rain or irrigation, the plant takes up water faster than the skin can grow and the meat of the tomato swells splitting the skin starting at the stem and progressing down the fruit.
Mulching the plants helps a great deal as well as deep watering.

I don't know that it helps with preventing tomatoes from splitting. However, Tums including generic versions of Tums, are amazing calcium for tomatoes. I plant one Tums per tomato plant. This allows for a consistent slow release of calcium per rainfall or per each time watering. It's the perfect inexpensive calcium solution that feeds them all season long. I highly recommend doing this if you grow tomatoes.