Many cannot have dairy due to an intolerance or allergy (or preference). You really don't have to have dairy as your calcium source. Dark leafy greens have calcium with collards being one of the highest sources. Collards are also low in oxylates so less of an issue than say spinach which is high in calcium but not as bioavailable due to high oxylates. Heat inactivates some of the oxylates so cooking is best. Kale, bok choy, broccoli, canned salmon and sardines with bones, white beans, sesame, tofu (only the ones coagulated with calcium, not magnesium), almonds, figs and a little less so, oranges all have calcium. Gerolsteiner makes a carbonated plain mineral water which has 130 mg calcium in a 12 oz serving. One of the highest sources of non-dairy calcium i have found is black tahini. It takes a little more thought and effort to put together a diet low in dairy and high in calcium but it's really doable. If you are going to include dairy, best to use organic, fermented dairy like kefir or an A2 yogurt both of which have beneficial probiotics and are more highly digestible.

You can calculate your daily calcium on cronometer.com, a free website. It's terrific. Just plug in what you ate and you can see if you hit your target. If not, you can take only the supplementation you need to fill in the gap. Tums is not really a great supplement to use as it contains calcium carbonate which is not a very absorbable form of calcium (it is derived from rock). Calcium citrate is gentler on the stomach and more absorbable and does not need to be taken with food.