New tank high alkalinity

[Basile]

I'm not sure why.


PH 8.0
grav 1.0235
Amonia 0
Nitrates 0.2
Nitrites undetectable.
KH 14.4


Stocking;


6 chromis
3 urchins
nassarius snails
7 hermiths


bubble coral
zoos
GSP patches
some macro algaes ( cheato- caulerpa, red algae) In starfire display refugium
Recent algae diatom bloom, because i fed the zoos which i'm told i should of done.


2 Dc pumps 950gph running to both the display refugiums and starfire tank
Reef Octopus 3000 working not really skimming anything.
Running GFO and carbon reactors
Lights 12 h cycles with including 3 h of actinics
Powerheads 5 controlable Tunze 6095 and 6055 in both tanks.


Display refugium feeding Reef by gravity.


Both tanks 2 " sand bed. Last water change 2 days ago.


How do i deal with this high alkalinity? Thanks for your time.