CO2 Scrubber Causing Abiotic Precipitation

[twentyleagues]

I would double check your testing first and foremost. Get a second test kit for alk. im not understanding how your tank is using that much alk. Is it in a basement with 0 air flow?

 

[iamacat]

Update:

I did about a 15% water change on Friday morning before I left town for the weekend. I left the dosing pumps off and the CO2 scrubber on. I tested this morning (Monday) for alkalinity and calcium and my calcium dropped about 10 ppm to 410 and my alkalinity dropped from about 7 dKH to 5.5 dKH. I don’t think this no dosing thing is sustainable!

If you keep dosing all you are doing is hardening your sand. You have nothing else using that much alk. It’s going to take longer than a weekend to correct. You also need to break up the sand clumps

 

[Trenton Henderson]

I understand, I really do. If I dose while precipitation is occurring, it will only lead to more. This being said, for the one candy cane that I have, 5.5 dKH is not great for it. I wanted to dose back up to where it wasn’t dangerously low for it.

Also, I’m just stating the trend I’ve seen: when CO2 scrubber is connected, I have more issues with precipitation because of the increased pH. When it’s off, it generally stabilizes.

I’m not trying to be ignorant of anything or anyone. I’ve been down the stop the precipitation road before and been successful, but it always comes back when my pH goes up.

 

[Randy Holmes-Farley Verified Community Expert]

Also, I’m just stating the trend I’ve seen: when CO2 scrubber is connected, I have more issues with precipitation because of the increased pH. When it’s off, it generally stabilizes.

That is certainly the expected result.

 

[Trenton Henderson]

That is certainly the expected result.

The sand must be not thoroughly plugged with phosphates yet if it precipitates that rapidly at 8.1-8.2 pH. Would you agree?

The highest level of phosphates I’ve been able to achieve is 0.02 ppm, and that’s only within the last month or so.

 

[Randy Holmes-Farley Verified Community Expert]

The sand must be not thoroughly plugged with phosphates yet if it precipitates that rapidly at 8.1-8.2 pH. Would you agree?

The highest level of phosphates I’ve been able to achieve is 0.02 ppm, and that’s only within the last month or so.

Precipitating calcium carbonate will bury phosphate that binds to the surface, leaving it still as a good seed crystal.

Magnesium, organics and phosphate all serve in the same way to slow precipitation of calcum carbonate.