Calcium reactor calculations

[klask]

Ca-addition through a calcium reactor is supposed to be “balanced”. That would mean that the same amount of carbonate are added as calcium. If I meassure the outcome of my reactor and make some calculations this does not seem to be correct. Please help me. Either my calculations or my assumption on the meaning of “balanced” are wrong.
Meassurements:
1. dKH 25 (9 in tank). delta 16 dKH
2. Ca (390 reactor, 300 tank) delta 90 mg/lit
Calculation example:
16 dKH = 16/2,8 = 5,7 meq/lit
90 mg/lit = 90/40= 2,25 meq/lit (40g/mol Ca)
This does not seem “balanced” to me. What is wrong?
(and yes, I have a bit low Ca-level… )

/Klas

 

[randy holmes-farley]

It looks very close to me. You get 2 meq/L of alkalinity for every one meq/L of calcium since each calcium carbonate has one mole of calcium and one mole of carboante, the latter of which provides two moles of alkalinity.

 

[klask]

OK thanks, I have missed the fact that one mole of carbonate provides two moles of alkalinity. And yes, in that case it is pretty close... Other measurements showed even closer to a factor two.

/Klas

 

[randy holmes-farley]

You're welcome.

Happy Reefing.