Beg to differ, PH and water hardness do have an effect on fish eggs and fertilization. Since the wild ancestors of Angels came from soft acidic water, many types of Angels still have that need to even want to breed as well as the percentage of hatch goes up in this type water. Even tho the fish can live in hard, alkaline water doesn't mean it will breed and breed sucessfully in it. Bottom line, if the spawns don't do well in your tap water, try RO
or even bottled spring water and see if there is a difference. That has worked for me in the past.