A fair number of literature indicates Sr is a poison.
To coral as well as to people.
A lot of reef aquarium literature of the 80's started pushing strontium
as a 'coral vitamin' after assays of Acroporid skeleta showed an
unexpected concentration of Sr, and some authors started yelling that
Acroporids NEEDED Sr. From there, manufacturers started claiming that
ALL corals needed Sr.
Not so. Some measurements of skeletal growth actually show Sr to be
a growth
inhibitor. Indeed, there are three theories for the
inclusion of Sr in coral skeleta:
that the coral needs it to generate skeletal material (apparently disproven
by measurement of coral metabolism w/ and w/o Sr present); that the
coral is irritated by ionic Sr, and locks it down as a compound in its
skeleton; that free Sr neither helps nor hurts, but isn't distinguished from
ionic calcium, and so is included in skeleton building. (Mg is also ionically
similar, and also gets incorporated.)
Besides, free Sr quickly gets free-coprecicpitated with CaCO3, and most
of the 'reef-addititve' Sr is helplessly handcuffed to other ions.
Just something to consider