no i dont feel its critical my reef runs at 8-9 and i have had it as low as 7's i dont think its guna harm anything but i would try to raise it back up key things is stability
sps might be affected more by a low alk that other corals
people will say 10-12 but i dont think thats what it needs to be when natural saltwater is at 7-8 dkh y run it higher
i hear colors pop better on sps at higher alk but who knows