Efficiency of Ca reactor

[Bojan]

Efficiency of Ca reactor.

I define efficiency of Ca reactor as

grams of Calcium carbonate dissolved/ grams of CO2 used

What is theoretical limitation ?

[Randy Holmes-Farley]

Well, that depends on the theory. :D

It will take some CO2 to reduce the pH to the point where any CaCO3 will begin to dissolve.
Ignoring that, then if you assume that the process is:

CO2 + H2O + CaCO3 ---> Ca++ + 2HCO3-

Then 1 CO2 molecule dissolves one CaCO3 equivalent.

So 44 grams of CO2 will dissolve 100 grams of CaCO3. :)

[Bojan]

Thanks.

Based o long term notes about replacing medium and CO2 , I found that my Ca reactor dissolve approximately 2kg of media with 1kg of CO2.

Based on theory this is quite good result and it is not possible to improve a lot.

[Randy Holmes-Farley]

That does sound pretty good. :)

[Bugger]

How low should the Ph be in the reactor?

[Randy Holmes-Farley]

The pH will typically be in the mid 6's in a single stage reactor, but I'd target the effluent and tank alkalinity rather than the reactor pH.

These may help:

Calcium Reactor setup calculator (CaCO3/CO2 reactors)
http://home.comcast.net/~jdieck1/reactor.html

A Guide to Using Calcium Reactors
http://www.reefkeeping.com/issues/2002-05/sh/feature/index.php

[Bojan]

I have pH=6,5 in reactor.