Do tums (calcium carbonate) cause indigestion due to lowering stomach ph ? does this stop the release of enzymes in the small intestine b/c thechyme isn't acidic enough?

It depends: That's a good question. In the short-term, Tums (calcium carbonate) can help reduce stomach acid and can be soothing for indigestion. But chronic long-term use of Tums (calcium carbonate) can up-regulate acid production, and eventually lead to worse acid reflux.

Not that way: Tums (calcium carbonate) act as antacid (for the acid already made), and will raise stomach ph. Small intestine is alkaline not acidic. Tums can cause constipation (all calcium supps can), gassiness, bloat, calcium carbonate can increase risk for kidney stones (calcium citrate won't-as much). Calcium also stimulates stomach to produce more acid.