Grow Mediums Need help understanding how my plants will use calcium compounds in my feed.

[SweetSkunk]

Hi all,
This is quite chemistry heavy
So straight to it:

I have hard water with high levels of CaCo3 (calcium carbonate).

When I add phosphoric acid for my pH down, a reaction takes place (making the water cloudy for a while and leaving a white residue at the bottom of the water resivour)
This reaction I have found out is this:
"Calcium carbonate reacts with phosphoric acid to produce calcium phosphate, carbon dioxide, and water."

so my questions is, growing in Coco:

1. Can the plants use calcium carbonate thats already in my water
2. Can my plants use Calcium phosphate in my feed after the reaction
3. Are either of these compounds detrimental to the plants.
4. Is Calcium phosphate the residue I see in the resivour and if so, it must be insoluble and not useful to the plants?

cheers
ss

EDIT:

If I were to use Nitric acid (which is suggested by the nutrient brand) another reaction would take place, producing Calcium Nitrate. Can calcium nitrate be directly uptake by the plants or does it require micro bio breakdown ?

cheers

 

[derek420colorado]

@BII or @Mañ'O'Green

 

[Mañ'O'Green]

Ok, yes the calcium carbonate in your starting water is usable by the plant as calcium. When you add the Phosphoric acid some of that calcium carbonate forms calcium phosphate that is usable by the plant as phosphorus. This is better for the plant in bloom since it needs more phosphorus then. When you use Nitric acid it forms some calcium nitrate which is nitrogen for the plant. This is better in veg because the plants need more nitrogen in this phase. The calcium carbonate that you see falling out of solution is locked up and not available to the plant but lowers the PH in the solution.

 

[SweetSkunk]

Thank you mate! I get all of what your saying.
The thing that was jarring me is, as I've gone from organic growing to Coco, I'm not sure what elements and compounds plants can use without the need of them being broken down by microbes. (other than these calcium compounds you've helped me out with )