Calcium additives

[TRS]

Originally Posted by Starry

Alk: 9.8 DKH
PH: 8.3
Calcium 340

I'm using IO salt.
1" Caribsea Seafloor Special Grade Sand (sposed to help with Ca, but ph would have to be low I would think)

What would be the best Ca additive to use? Preferably liquid.

CaribSea PURPLEUP has my vote for a Calcium liquid, but The Reef Shoppe also sells the granular Calcium Chloride Dihydrate as an alternative DIY Calcium additive.