Kalkwasser vs Soda Lime

[SolusCado]

I have a protein skimmer recirculator setup running soda lime to extract CO2 from the air used by the protein skimmer. On more than one occasion, the skimmer has overflowed, and sucked water in through the recirculator, causing a spike in PH. Notably, the whole point of the recirculator IS to increase PH...

I know that soda lime contains Calcium Oxide, and people are already dosing their tanks with Calcium Hydroxide to boost their PH. This leads me to wonder what exactly I should be checking when I get a dose of Soda Lime into my tank like this. Is it even bad? Should I actually run water through it so that I CAN boost my PH higher... What would be the negative effect of doing this? What else should I be monitoring to see the negative effects?

 

[Randy Holmes-Farley Verified Community Expert]

The concerns for a small amount of fluid are:

1. Unknown impurities in soda lime might get into the tank
2. Calcium carbonate and magnesium hydroxide may precipitate on the soda lime, potentially ruining it.

The concern if a lot of fluid recirculated is dropping alk and calcium and magnesium via #2.

Depending on what exactly happened with respect to flow into the taak, it's also possible the tank alk and calcium may rise.

 

[SolusCado]

The concerns for a small amount of fluid are:

1. Unknown impurities in soda lime might get into the tank
2. Calcium carbonate and magnesium hydroxide may precipitate on the soda lime, potentially ruining it.

The concern if a lot of fluid recirculated is dropping alk and calcium and magnesium via #2.

Depending on what exactly happened with respect to flow into the taak, it's also possible the tank alk and calcium may rise.

Thank you.

 

[Randy Holmes-Farley Verified Community Expert]

Thank you.

You're welcome.

Happy Reefing.

 

[Hans-Werner]

I can add one more concern:

Soda lime contains sodium hydroxide which will not only increase pH but also alkalinity/KH in a way that is hard to predict. This will precipitate more calcium than the pH increase alone would and create an imbalance between calcium and alkalinity/KH.