PDA

View Full Version : Ok, I may be way off base here


Zedar
12/15/2006, 02:56 PM
Randy, or anyone else with the knowledge. Got a question to ask.
It may be screwy but here goes.

I have a calcium reactor that i took off line. (for reasons that id rather not get into here)

I was getting ready to empty the media when it struck me.

What if I ran this in a closed loop and ran the co2 wide open, dissolving the the media into a dissolved solution? Then use the balanced solution in place of calcium and alk?

Don't beat me up too much :)

bertoni
12/15/2006, 03:14 PM
I think the CO2 would outgas over time if the solution was not stored in an airtight container. As the CO2 outgassed, I would think you'd see a lot of precipitation. It'd take a fair volume of water to dissolve all the media, for that matter.

Zedar
12/15/2006, 03:16 PM
Thanks Bertoni for the prompt answer :)

bertoni
12/15/2006, 03:38 PM
Well, let's wait for Randy's opinion...

Randy Holmes-Farley
12/15/2006, 04:50 PM
You won't be able to make it all that much more potent than reactors normally do, unless you pressurized the CO2 and held it elevated. The higher the alkalinity in the water, the lower the pH needs to be to dissolve more CaCO3, and the lower the required pH, the more pressure of CO2 is needed.

You cannot have dissolved concentrated CaCO3 in a water solution that is stable. It will release CO2 to the air and CaCO3 will precipitate.

Zedar
12/15/2006, 10:51 PM
I see. So it only stays in solution when theres C02 in the water, and the PH is low?

Randy Holmes-Farley
12/16/2006, 07:01 AM
Yes. :)

The carbon dioxide reduces the pH, converting the carbonate to bicarbonate. It is the concentration of calcium and carbonate in the water that limits the solubility of calcium carbonate. If you allow the CO2 to get out, the pH rises, bicarbonate turns back to carbonate, and calcium carbonate reprecipitates.

Zedar
12/16/2006, 09:50 AM
Thanks again :)

Randy Holmes-Farley
12/16/2006, 10:56 AM
:thumbsup:

Happy Reefing. :)