Oops… Dry Ice

[reefiniteasy]

So from yesterday midday until this evening I’ve had a decline in pH. My scrubber media is only half depleted. I really couldn’t figure out why pH was lower than normal.
Well, yesterday my wife got her latest shipment of Nutrisystem frozen meals. It comes in a large styrofoam cooler with a giant brick of dry ice. I was supposed to take the dry ice to school with me so I can make dry ice bubbles with my students. I forgot. When I got home my wife was complaining of a headache and told me to get the cooler out. That’s when I realized I forgot the dry ice. When I popped the top on the cooler, the dry ice had completely sublimated. @Randy Holmes-Farley can a large brick of dry ice have such an effect on the tanks pH? Usually we put the cooler and dry ice in the garage or I leave the dry ice on the driveway. This is the first time we let it sit in the house all day.

 

[KrisReef]

Lower pH from pumping CO2 enriched air into a skimmer maybe?
Headache from breathing the same air?

 

[taricha]

let's ballpark an average house....
2500 ft^2 x 8 ft ceilings = 20,000 ft^3 = 566 m^3 of air volume.
566 m^3 x (density of air = 1.2 kg/m^3) = 680 kg of air in the house.
CO2 is normally 0.063% by mass of air so 680kg x 0.00063 = 0.43 kg of CO2.

So a 1kg CO2 block would have more than double the CO2 in an average house-sized volume of atmosphere. Subliming it could triple the indoor CO2 in the whole house.
Totally expected that addition would be measurable in tank pH. Especially if it was left nearby.

 

[reefiniteasy]

let's ballpark an average house....
2500 ft^2 x 8 ft ceilings = 20,000 ft^3 = 566 m^3 of air volume.
566 m^3 x (density of air = 1.2 kg/m^3) = 680 kg of air in the house.
CO2 is normally 0.063% by mass of air so 680kg x 0.00063 = 0.43 kg of CO2.

So a 1kg CO2 block would have more than double the CO2 in an average house-sized volume of atmosphere. Subliming it could triple the indoor CO2 in the whole house.
Totally expected that addition would be measurable in tank pH. Especially if it was left nearby.

Wow! Thank you for calculating that. I think this may have happened once before too now that I think about it. From now on the dry ice immediately goes outside.

 

[Randy Holmes-Farley]

Yes, dry ice can have a big effect.

I once thought it fun to add a small piece to my sump.

The pH in the sump crashed to around 5. Luckily, it wasn't nearly that low in the main tank, but it certainly had me rethinking my stupidity. lol

Think of that experiment this way.

Normal air is 400 ppm CO2.

The CO2 bubbles coming off dry ice are 1 million ppm.

You can see how a million ppm of CO2 will drop pH an awful lot. lol