tiny white border when collapsing border appears

Question

I've collapsed the border on my table but a tiny white border appears. Do you know how to get rid of this?

Image showing white border

Part CSS:

#table tr {
                    max-height: 12.20px !important;
                    height: 12.20px !important;
            }

            #tblContainer {
                    width: 1191px;
                    height: 842px;
                    margin: 0 auto;

            }

            #table {
                    table-layout: fixed;
                    width: 100%;
                    height: 100%;
                    border-spacing: 0px;
                    zoom: 0.80;
                    border: 1.5px solid grey;
                    border-collapse: collapse;
            }