CO2 effects in a small apartment

KMSReefer · Mar 2, 2018

My tank has officially been up and cycled for a year now and I am generally very happy with how things are going. I seem to be able to keep any coral and everything has good polyp extension and is growing. I am away from my tank a lot and recently took the plunge and got an apex. I always knew my pH wasn't ideal but I never really knew the extent.

I am in my last year of engineering and am living in a one bedroom apartment with my wife and our dog. I just wanted to post some apex graphs showing how extreme my pH swing is and see if anyone has any solutions. I have confirmed the values using salifert tests as well as a lab grade pH pen and I have recalibrated my probe multiple times.

The first graph shows the four days that I was in the apartment with time I was away before and after, the second graph shows when I was away for a week and came home (the pH rise plateaus within 15min of me getting back before continuing to rise).

My parameters are:
Salinity = 35.5ppt (Refractometer)
Alkalinity = 223 ppm (Hanna)
Calcium = 463ppm (Hanna)

And just for reference a shot of my tank.

zachxlutz · Mar 2, 2018

I notice swings in my 3BR house with our 2 dogs and myself/girlfriend. If we're away, it's much higher, if we're home it dips and if we have company it dips even more. I even have my skimmer plumbed to pull air from a window I keep cracked. CO2 buildup is real!

KMSReefer · Mar 2, 2018

I have tried plumbing the skimmer outside but it made such a small difference that I unhooked it. In a way its entertaining because when I'm home, growth isn't very fast but if I go away for a weekend or more, everything takes off. If I spend a day in the house my pH will dip as low as 7.7.

Randy Holmes-Farley · Mar 2, 2018

More aeration will reduce that day to night swing. The swing itself is not a concern, IMO, just the minimum.

The minimum can also be brought up by using a CO2 scrubber on the skimmer air inlet, or a very high pH supplement (based on hydroxide instead of carbonate or worse, bicarbonate)

Randy Holmes-Farley · Mar 2, 2018

FWIW, some people see a big pH drop in their tanks when they have a big party in the same room as the tank!

KMSReefer · Mar 2, 2018

Randy Holmes-Farley said:
More aeration will reduce that day to night swing. The swing itself is not a concern, IMO, just the minimum.

The minimum can also be brought up by using a CO2 scrubber on the skimmer air inlet, or a very high pH supplement (based on hydroxide instead of carbonate or worse, bicarbonate)

I do use your recipe for a carbonate based alkalinity supplement currently and I plan to switch to the hydroxide based supplement once my supplies run out. If I'm honest, I'm not super concerned with my current pH as things are growing well and the skeletons being formed by my coral are strong. In another month or two, I will be able to open windows which will help a lot. Its more something I found interesting and if I can find a solution that works then its all the better.

Randy Holmes-Farley · Mar 2, 2018

KMSReefer said:
I do use your recipe for a carbonate based alkalinity supplement currently and I plan to switch to the hydroxide based supplement once my supplies run out. If I'm honest, I'm not super concerned with my current pH as things are growing well and the skeletons being formed by my coral are strong. In another month or two, I will be able to open windows which will help a lot. Its more something I found interesting and if I can find a solution that works then its all the better.

That all sounds reasonable.

KMSReefer · Mar 22, 2018

I just wanted to post an update on this thread regarding my pH issues as they have been completely resolved. First off, I did not end up switching to the higher pH alkalinity additive as the issue was fixed before I ran out of my old 2 part. I can't say for sure what the fix was as I made a few changes all at once but all of the changes were associated with increasing my macro algae growth.

I keep chaeto, blue hypnea, and red gracilaria. The chaeto is grown in the sump and the other two are both in the sump and the display. In an attempt to increase their growth I switched my refugium light to a warmer spectrum and also increased the red and white spectrums on my display lighting. Initially this worked great but the blue macro started looking bland. After testing my water I decided to increase my iodine dosing and dose iron. This brought the color back and increased the growth of the macro a lot. In this time I also noticed an increase in growth from my coral. My pH has also increased to nearly the ideal range of 8.2 to 8.4 throughout the day as shown below