Emergency: Protein Skimmer Overflow / CO2 scrubber. DROP in Alkalinity

[GoodKat]

I am having a rough week. and need some help figuring this out.

I use BRS soda lime pellets on a recirculating CO2 Scrubber / protein skimmer set up.

Tonight the protein skimmer over flowed and began sucking some water through the soda lime pellets and CO2 scrubber. The contaminated soda lime water got in to the tank.

My PH is 8.35 / Calcium is 470.
But my ALK is 5.0!? I tested with a Hanna Checker and double checked with a RedSea kit. What could be going on here? Shouldn't the soda lime water increase the ALK? ?

I am so confused. I am doing a massive water change to get my ALK back to 8.4 as quickly as possible.

 

[fishguy242]

i'm puzzled ,alk would be higher?? reaction giving false readings?? @Hemmdog ??.. @vetteguy53081 ??

 

[GoodKat]

i'm puzzled ,alk would be higher?? reaction giving false readings?? @Hemmdog ??.. @vetteguy53081 ??

Right? I was shocked, but I tried two different test. Hanna Check and RedSea and checked multiple times. Could it be a color changing chemical in the soda lime? I have no idea how ALK would drop

 

[fishguy242]

i just cannot see alk that low with ph 8.3..???????

 

[vetteguy53081]

It should increase PH with external air source. Alk will alter somewhat but scrubber increases ph value.
Because it foamed up and overflowed, the soda lime may have restricted flow causing circulation to diminish thereby increasing the water level in skimmer

 

[GoodKat]

This too weird. I am confident in my test because I ran two different type. Calcium and Ph remained up change, only the ALK dropped.

I tested what would happen if I added the BRS soda lime to salt water with lots of airation and unsurprisingly the Ph and ALK spiked.

I have no idea whats going. Rather than try to bring up ALK with soda ash or additives I am going to do water changes.

 

[fishguy242]

following ,keep us updated,nothing too drastic in water changes,no big swings

 

[GoodKat]

Okay I think I have a working theory for anyone that finds this thread in the future. Documenting in case it helps anyone. Please chime in you know more about water chemistry.

I think because there was some water flowing through the CO2 scrubber chamber with soda lime pellets and being sucked back into the protein skimmer , the ALK was precipitating out in the form of crystals.

Although I did not see any evidence of precipitation on pumps or in my sump, the skimmer definitely had a thin white film.

In addition, the media was very clumpy when I cleaned it out the CO2 scrubber. Logically the Alk had to go somewhere in the tank, and I think it was forming calcium carbonate crystals. This still slightly odd because my calcium didn't drop.

I checked my Mg (after a very large water change 30% with red sea pro) and it still seemed low, around 1300-1320. I normally keep it at 1380-1400. Maybe this is evidence of precipitation?

I caught the overflowing problem within 8-12 hours. Maybe alkalinity ions were pulled out of the water faster than calcium?