Ambient CO2 too high

[Spectuhcle]

I have a tank in my office that I struggle with the ph. Without any mitigation methods i will have a ph of about 7.6 (anywhere from 7.4 if I'm in my office a lot to 7.7 on a good day) I have had this tank up and running for about 14 months now and I've tried many things to get the ph up into the 8s. I would love 8.3 but I'll take what I can get. I run an alk of 9 (It bounces back and forth between 8.5 and 9.5 as every time I get my dosage down the corals seem to change their uptake and get mad for one reason or another). I keep Calcium between 500 and 550. (I think this is definitely on the higher side but that's what my lfs suggested). I have my magnesium in the mid 1400s (I don't worry about that one as much as maybe I should). Nitrate flucuates between 7 and 13 depending on if I have to be out of town for the weekend or something. Phosphate has been pretty steady around 0.3-0.5 for the last couple months now. I have a Hippo Tang (4 inches), a Magnificient Foxface (4 inches), 2 clowns, a firefish, a manderin and an anthias as well as cleanup crew, and mixed reef of frags with nothing except a mushroom that has really taken off growth wise. The red monti does well too but everything else is just existing with basically no growth.

I would just like to list the things that I've tried in order to get my ph to come up and see if anyone has any suggestions for me.
- Refugium. Doesn't really seem to do anything ph wise. I have tried only lighting at night and lighting it around the clock and neither really has any effect on the ph of the tank.
- CO2 scrubber (connected to a reef octopus 110SSS)
- Pulling room air. This definitely works a little bit. It will keep my tank between 7.7 and 7.8 not really as high as I'm looking for though
- Recirculating. I'm not sure this raises the ph any more than just pulling from the room but it makes the media last longer but I also have run into the media getting too wet
- Running the skimmer tube out the window. I find that this also does about as well as the CO2 scrubber and in my apartment I can't really do this long term as I only have a window to put it out and at that point I might as well just open the window and ventilate the whole room.
- Leaving the window open. This again will bring the ph up to around 8 but I can only do this about 25% of the time due to weather and I think I would rather have low ph than a ph that swings so much. Also my screen isn't great and it lets bugs in.
- Dosing for ph boost.
- Sodium Carbonate (Soda Ash). Didn't really see any difference
- Calcium Hydroxide (kalkwasser). I'm not sure I see much impact of this. Maybe 0.05 increase maybe... And it's a pain to dose because I don't have room for a container to hold it.
- Sodium Hydroxide (lye). Same result as the kalk but it's easier for me to dose. (I currently dose around 20ml/day at using Randy's suggested concentration of 283 grams of sodium hydroxide to 1 gallon of rodi to my tank to maintain 9dkh on what I think is around a 75 gallon water volume. I dose it as frequent as my red sea doser will let me which I believe is 24 times a day)
On a normal day I will sit in my office and work from home and my office (and the rest of my apartment isn't much better) will reach upward of 1600ppm CO2. Although I have seen as high as 2200ppm). My building just finished construction when I moved in so everything is brand new. I have tried to look into some sort of ERV or HRV (still not sure what the difference is) but I have only seen ones that hook into an HVAC system that I don't have access to since it's an apartment.

The best total solution that I have been able to come up with so far is as follows:
- Run my refugium during the night to balance out the ph swings
- CO2 scrubber just pulling from the room right now to avoid the headache of water collecting in the media
- Dosing Sodium Hydroxide to buffer up to 9dkh
- This still only keeps my ph between 7.7 and 7.8 and when the media depletes it sometimes will get below 7.7

Some things that I have though of that I might try next but I have no idea if they would work:
- Larger skimmer. Larger section for the CO2 scrubbed air to diffuse into the water and CO2 to leave? Sounds like it might have an effect but I haven't seen anyone try this to see if it improves results or not
- Raising alk to 10 dkh. I'm not sure where the danger zone for my fish and corals are so I've been really reluctant to go this route. Especially because I'm not even sure if it would help that much.
- Trying to reduce surface agitation on the top of the tank. I have to assume that's the biggest "leak" letting CO2 in at this point but I don't want to sufficate the fish and corals of Oxygen either.
- Maybe finding a way to cover the filter socks as there is a fair amount of agitation in that section of the sump
- I've seen a few things about bubbling skimmer air through a hydroxide solution and maybe that is more powerful than the current co2 pellet media.

Does anyone have any ideas other than the common resolutions I've listed above? I feel like I've tried everything and I just can't seem to keep the co2 out of the tank

 

[KrisReef]

What are you trying to raise pH for? What would be the point of pH 8.3?

 

[Spectuhcle]

What are you trying to raise pH for? What would be the point of pH 8.3?

Coral growth

 

[rishma]

Connecting outside air to my skimmer last year really didn’t help my pH much. I suspect my skimmer just wasn’t large enough. Not sure. A CO2 scrubber just required to much maintenance, but was effective until media was spent.

I recently had an overdose of nopox, (comedy of errors nobody would believe), and I was very concerned about a bacterial bloom and oxygen depletion. To counter this I ran an air pump outside and put a diffuser in the rear chamber of my AIO tank. Long story short, I never had a bacteria bloom but I did see pH rise and become more steady after a few days. It worked so well that I left it running for a few weeks and my average pH increased by 0.1 consistently, regardless of open windows or closed.

I ended up drilling a hole in an external wall and permanently running an airline and diffuser in the section of the overflow I were a filter sock would go (I don’t use one). I am pretty happy with my pH now, ranges between 8.15-8.25. Higher than it’s ever been.

If I wanted to make it even higher, I’d use a RHF 2-part for extra pH boost, but for now I plan to leave it as is.

 

[Randy Holmes-Farley]

If you cannot readily bring more fresh air into the room, then I think you've tried most of the ways that are generally successful.

All I can think of to go forward, aside from living with it, is to try to reduce aeration that is not coming from outside or scrubbed air, such as the tank top.

 

[Spectuhcle]

Hmm yeah unfortunately that's what I was thinking too. I'll have to see if there's some realistic way to ventilate through the window without tanking the temp in the room and also keeping the bugs out. Thanks

 

[rishma]

If you cannot readily bring more fresh air into the room, then I think you've tried most of the ways that are generally successful.

All I can think of to go forward, aside from living with it, is to try to reduce aeration that is not coming from outside or scrubbed air, such as the tank top.

I have never tested it, but I assumed with my skimmer pulling in room air, the surface agitation in the tank was having a negligible impact. But perhaps I have this wrong, and surface agitation with room air in fact overwhelmed the outside air to the skimmer which is why I saw little affect.

 

[bobnicaragua]

Hmm yeah unfortunately that's what I was thinking too. I'll have to see if there's some realistic way to ventilate through the window without tanking the temp in the room and also keeping the bugs out. Thanks

I closed a pool noodle in the window behind the tank and run a large airline into my DIY carbon filter. I then run 2 small lines from the filter to the skimmer.

 

[killer2001]

You'll need an air exchanger that fits into a window and its held down by the weight of the window. I have a room dedicated to my aquarium and originally I was seeing about 1000-1200 ppm CO2 in the room. Once I installed the air exchanger I am now seeing 500-600 ppm CO2 and my pH went from 7.8 - 8.0 to 8.1 - 8.3.

Instead of blowing fresh air into the apartment, you'll want to have the air blowing out. You may need multiple units to achieve desired results depending on how large the apartment is. I live in Florida so I have to do it this way otherwise the room would be filled with hot moist air. I also bought a dehumidifier for the room to maintain a level of 50% humidity at all times.

 

[Spectuhcle]

You'll need an air exchanger that fits into a window and its held down by the weight of the window. I have a room dedicated to my aquarium and originally I was seeing about 1000-1200 ppm CO2 in the room. Once I installed the air exchanger I am now seeing 500-600 ppm CO2 and my pH went from 7.8 - 8.0 to 8.1 - 8.3.

Instead of blowing fresh air into the apartment, you'll want to have the air blowing out. You may need multiple units to achieve desired results depending on how large the apartment is. I live in Florida so I have to do it this way otherwise the room would be filled with hot moist air. I also bought a dehumidifier for the room to maintain a level of 50% humidity at all times.

wouldn't that mean I just get the air from the rest of the apartment in my room. If I had enough ventilation it would maybe come from the the hall way which I haven't tested but I'm guessing it's not much better because it's well trafficked. Wouldn't the best result be blowing in to displace the inside air into the rest of the apartment and the air in my office becomes lower in co2

 

[killer2001]

I suppose it depends. It will take longer to see results, but I would try sucking the air out first. Otherwise, if you decide to blow air into the room from outside, you will have to regulate temperature and humidity.