Calcuim Carbonate

I was wondering if anyone has used calcuim carbonate in their water.
I am the one that posted about the calcuim bentonite on july 28.
est.. about 9000 gal pond. Green pea water.
I have been adding a coup of BS in my water every day for 4 days.
My readings are Amonia 0
Nitrite 0
Nitrate 0
Total hardness still 10
Total alkalinity still 60
PH is still 6.5

Hubby said if I was trying to make the water hard I needed to use Calcuim
Carbonate. He can get some at work.
Anyone use this or have thoughts?
Also some guy he works with told him to tell me to buy a roll of barley
straw and throw it in my settlement chamber.
I didn't think this worked for green water, just the stringie algae.

Priss