best way to get calcium on acid reflux/gerd diet?

I am told the LES valve needs calcium, that we should be getting 1000mg calcium a day. If off dairy I find this very difficult. Calcium rich foods still don't have enough. I am finding calcium supplements give me reflux issues. I have tried a sea vegetable based calcium and calcium citrate. Is there a more gentle calcium I can try? If someone could advise on the most gentle calcium supplement that would be a big help.

Thanks!

I take Citrical petites, it was recommended by my doctor.