Excessive CO2 Levels

[Dolomiteclay]

Sorry about the long post in advance. As the subject would suggest, I'm observing some low pH values in my tank and although it doesn't appear to have any negative impact on the inhabitants (LPS, SPS, Clams, anemones, etc.) nothing I do really works.

I'll start with my parameters.

65 gallon predominately lps with a 20 gallon sump
pH-7.6-7.8
Alk-9-11
Ca-380-420
NO3-2.5
Mg-1300


Dose 12ML every 8 hours of Bionic CA and Alk.

My pH measurements generally come from a probe that is hooked to my archon and I have updated the archon as well as and calibrated the probe several times. I have also confirmed these values with multiple test kits.

Last month my old skimmer had to be replaced and I got a new one. I moved down in a size to a BM 5 that has a smaller pump than the old one. Since I live in a new apartment I run a CO2 scrubber hooked up to the air intake of my skimmer in order to keep my pH around 8. After a few days of running the new skimmer I noticed that my pH was hovering around 7.8 and that the media in the reactor was not expiring (changing color) as quickly. Seeing as how it is a smaller skimmer with a smaller pump, I just assumed that it was taking in less air than the other and decided I would add air stone to my sump in order drive off some of the excessive CO2 in the water. That has helped some, but my pH still maxes out at 7.8 and drops to 7.6 at night.

The good thing is that this issue is not harming my livestock. However, I just can't believe that I still have that much CO2 in the tank. I have even had the windows open recently due to the warm weather in Texas. Any ideas on what could be causing the excessive CO2 levels and subsequent low pH values would be appreciated.

 

[karimwassef]

I don't trust probes unless calibrated frequently.

I would test with a kit for reference too.

Personally I use two probes to avoid getting meaningless inflections and deviations.

Not that pH is that impactful, but I would double check your measurement anyway.

 

[bertoni]

If the measurement is correct, then more aeration might help, particularly if the room is getting lots of outside air. Checking the water surface for any film or coating, and tuning the skimmer both might help, although problems there are fairly uncommon.

 

[Kurt03]

I have a netatmo which is a fancy weather indoor/outdoor temp humidity sensor that connects to your phone. Fun thing is that it also monitors co2. I have a pH probe in my tank, it's very easy to see the correlation of co2 buildup in the house/room and it suppressing the pH in the tank. If I notice it, running the circulation fan in the house can help, but not sure how much it will do in an apartment. What about a o2 reactor kinda like an ozone reactor and pull outside air with the air pump.

 

[karimwassef]

You can run an injection penductor with an outside line intake

 

[Arthur1]

As kurt mentioned, I was thinking ozone as well. Fresh air (one way or another) isn't a bad idea either.

 

[Fitzreefer]

Outside air to the skimmer line is best, and I understand that CO2 scrubbers work well too. I use outside air. Downsizing the skimmer may have reduced the CFM of air it draws in. Knowing that I was creating and outside air intake, I particularly compared the CFM rating of the various skimmers before selecting one. I ended up up sizing my skimmer. Running an air stone from an air pump that is drawing on CO2 laden air within the room is likely going to equalize the CO2 in room to your tank water. I was doing the same and stopped that when I understood this subject a bit more more. A circulation pump in the sump can help with any film in there, without all the salt creep and additional CO2 induction.

Sent from my XT1080 using Tapatalk

 

[Dolomiteclay]

Sounds like I need to run an air line to my window. I can't really drill any holes since I rent, and have been hesitant to do this since I will have to leave the window cracked all the time and Houston summers can be a little warm.

 

[karimwassef]

Get a wood spacer that fits the gap in your window and drill a hole in that. If you want to seal it, use foam board on the inside and even caulk around the hole.

You can even use window and door rubber gasket (long strips) to seal the wood against the window frame.

Having fresh air to the tank doesn't need to be at the expense of the electricity bill.

 

[oseymour]

I don't the airline is going to help much if the issue is excessive C02. More surface agitation will help a little - again if the issue is excessive c02 in the apartment then the agitation is only going to draw more of the air in the room inside the tank.


I added the BRS C02 scrubber and it worked but it was exhausting the media too fast. So I just run a line from my skimmer air intake to outside my apartment. I use foam insulation to seal the window with only enough room for the airline to go outside.

I oversized my skimmer so I know it's pulling in a lot of air.

In my tank higher PH leads to a higher growth rate, my tank uses alk faster and I see more white tips on my sps indicating growth.