How I fixed it — CO2 and PH

[Biologic]

I went through the “stages of grief” and wound up at “acceptance”. CO2 is the problem. I went through Randy’s guides to pH to disprove CO2 influence. I made this post showing a lot of steps of diagnosing the problem.

Though I don’t have to “accept” that I have to live with it. What I did to cure my pH issue.

1. Critical — Get an oversized skimmer, run the airline outside. I originally had a Deltec MCE300 skimmer, which I upgraded to a Deltec MCE601 skimmer. As far as hang on the back skimmers go, Deltec likely produces the fairest rated HOB skimmers. My tank is 28 gallons, and the MCE601 is rated for a 120 gallon. Drawing 400 liters per hour of air. Results — it brought my average up from 8.0 to 8.12 and reduced my diurnal swing to 0.19. Nice high evening pH’s in the 8.2’s.
2. Giving CO2 Scrubber Another Chance — The big reason why these don’t work is that they are set up wrong. 1) You still should pull your outside air through the CO2 scrubber 2) the recirculating method isn’t very helpful, though I am still evaluating this. For now it’s just straight through 3) and most importantly the air draw has to be strong enough to make a difference. I proved this in a small volume running a air pump into 600 mL of water. The pH shot through the roof. Upgrading the skimmer with a larger air draw vastly improved the performance. This added another 0.12 to the average pH, now sitting at 8.24. I am hitting my average pH value now at 9 AM!!!! Nice high pH values around 8.30 at end of day.
3. Bigger skimmers can be run half the time — I have my skimmer set to turn off (Apex) when the pH hits 8.26. So around 10 AM my skimmer naturally shuts off. Then turns on around 9:30 PM. The skimmer remains on until my lights start influencing the pH in the morning. The lowest values at night are now 8.16, which quickly move up to 8.2 by 8 AM when more of my white LED’s turn on. Results — far more stable pH with a 0.15 diurnal swing

What didn’t work so well for me — kalkwasser believe it or not. It’s too difficult to control on a smaller tank and it was another confounding variable to control. Furthermore, It had actually the least affect. I used a saturated solution, dripped it through out the night via Apex DOS. It was the least effective because evaporation isn’t enough to meet the demand. The alkalinity quickly shot up. So it was a disaster. No loss thankfully.

Scaling this up for the future — I have plans on getting a much larger tank. This was my test tank, getting me back in after my 12 year hiatus from the hobby.

So equipment would need to scale with it to get these results. It’s crude, but i would like to say I can use a ratio to help put me in a ball park when building a tank that’s 6x the size of this one.

One consideration is that I use DIY All For Reef. I am sure when I go larger I will switch to a sodium carbonate solution for alkalinity, which I expect will not negatively effect the performance I’ve seen thus far.

 

[Scorpius]

This won't work for everyone. Only 100% way to raise ph if its co2 related is to reduce co2. Open windows 24/7 or have a heat recovery ventilation system added to your hvac unit.

 

[arking_mark]

Tuning a Skimmer / CO2 Scrubber for pH Control

On my reefing journey, I found Kalkwasse + Skimmer + CO2 Scrubber to be very effective for bringing my pH from 7.8 - 7.9 to 8.26 - 8.36. I guess most people would just leave it at that. However, I wanted to be more efficient with the CO2 scrubbing material so I wanted to implement a...

www.reef2reef.com

 

[BiggestE222]

I went through the “stages of grief” and wound up at “acceptance”. CO2 is the problem. I went through Randy’s guides to pH to disprove CO2 influence. I made this post showing a lot of steps of diagnosing the problem.

Though I don’t have to “accept” that I have to live with it. What I did to cure my pH issue.

1. Critical — Get an oversized skimmer, run the airline outside. I originally had a Deltec MCE300 skimmer, which I upgraded to a Deltec MCE601 skimmer. As far as hang on the back skimmers go, Deltec likely produces the fairest rated HOB skimmers. My tank is 28 gallons, and the MCE601 is rated for a 120 gallon. Drawing 400 liters per hour of air. Results — it brought my average up from 8.0 to 8.12 and reduced my diurnal swing to 0.19. Nice high evening pH’s in the 8.2’s.
2. Giving CO2 Scrubber Another Chance — The big reason why these don’t work is that they are set up wrong. 1) You still should pull your outside air through the CO2 scrubber 2) the recirculating method isn’t very helpful, though I am still evaluating this. For now it’s just straight through 3) and most importantly the air draw has to be strong enough to make a difference. I proved this in a small volume running a air pump into 600 mL of water. The pH shot through the roof. Upgrading the skimmer with a larger air draw vastly improved the performance. This added another 0.12 to the average pH, now sitting at 8.24. I am hitting my average pH value now at 9 AM!!!! Nice high pH values around 8.30 at end of day.
3. Bigger skimmers can be run half the time — I have my skimmer set to turn off (Apex) when the pH hits 8.26. So around 10 AM my skimmer naturally shuts off. Then turns on around 9:30 PM. The skimmer remains on until my lights start influencing the pH in the morning. The lowest values at night are now 8.16, which quickly move up to 8.2 by 8 AM when more of my white LED’s turn on. Results — far more stable pH with a 0.15 diurnal swing

What didn’t work so well for me — kalkwasser believe it or not. It’s too difficult to control on a smaller tank and it was another confounding variable to control. Furthermore, It had actually the least affect. I used a saturated solution, dripped it through out the night via Apex DOS. It was the least effective because evaporation isn’t enough to meet the demand. The alkalinity quickly shot up. So it was a disaster. No loss thankfully.

Scaling this up for the future — I have plans on getting a much larger tank. This was my test tank, getting me back in after my 12 year hiatus from the hobby.

So equipment would need to scale with it to get these results. It’s crude, but i would like to say I can use a ratio to help put me in a ball park when building a tank that’s 6x the size of this one.

One consideration is that I use DIY All For Reef. I am sure when I go larger I will switch to a sodium carbonate solution for alkalinity, which I expect will not negatively effect the performance I’ve seen thus far.

I have started supplementing my Kalk dosage with my no longer used AFR DIY solution. With just Kalk top off my ALK was dropping .2 per day. My CO2 scrubber. Raised my PH approx .4 per day.

 

[Biologic]

This won't work for everyone. Only 100% way to raise ph if its co2 related is to reduce co2. Open windows 24/7 or have a heat recovery ventilation system added to your hvac unit.

Right, mine was CO2 related, and I tried to say it wasn't, but it was, and most cases it is for many reefers. I cannot have my windows open 24/7 as I live in the coastal south, the heat and humidity would ruin my home. Heat recovery system is not a possibility in my case either. For me, this was very cost effective way to treat high CO2 in my home, without making any other adjustments to my home A/C or sacrificing comfort.

 

[Biologic]

Tuning a Skimmer / CO2 Scrubber for pH Control

On my reefing journey, I found Kalkwasse + Skimmer + CO2 Scrubber to be very effective for bringing my pH from 7.8 - 7.9 to 8.26 - 8.36. I guess most people would just leave it at that. However, I wanted to be more efficient with the CO2 scrubbing material so I wanted to implement a...

www.reef2reef.com

I am glad you shared your results of adding a bigger skimmer. I thought I came up with this idea independently lol. I figured if the little air pump is driving pH up outside from my CO2 Aeration Test, why not a larger skimmer? I easily hit 8.5 when I fed the CO2 scrubber in-line in an aeration test.

I really like the idea of adding a solenoid to draw in CO2 rich air to keep the value from going too high. I am still not 100% sold on the re-circulating method. I am going to get some more parts to see if it works on this skimmer set up.

For my next build, I am even considering running a recirculating skimmer remotely outside -- or even the sump completely outside. Maybe that's a bit extreme, but if I lived in a warmer climate, I'd do it.

 

[arking_mark]

I am glad you shared your results of adding a bigger skimmer. I thought I came up with this idea independently lol. I figured if the little air pump is driving pH up outside from my CO2 Aeration Test, why not a larger skimmer? I easily hit 8.5 when I fed the CO2 scrubber in-line in an aeration test.

I really like the idea of adding a solenoid to draw in CO2 rich air to keep the value from going too high. I am still not 100% sold on the re-circulating method. I am going to get some more parts to see if it works on this skimmer set up.

For my next build, I am even considering running a recirculating skimmer remotely outside -- or even the sump completely outside. Maybe that's a bit extreme, but if I lived in a warmer climate, I'd do it.

I'm far from the 1st as well. @Lasse did this well before me, as well as others.

The real benefit of recirculation is longer life for media and damp air. When I didn't recirculate I'd have pH glitches and have to troubleshoot. Was the media exhausted? Not damp enough? Etc.. Once I figured out the water added to the bottom was quickly being used up (which also reduces efficacy). I was constantly opening and adding water to the media container. Some setups even have a container just with water prior to the media chamber. I just went recirculation...no more problems with keeping the air damp with the added benefit of longer media life.

 

[Calm Blue Ocean]

Your results have me very tempted to upgrade my skimmer. I hate to go HOB with an AIO tank but I suspect it's the only way to get something with enough power. Great post, very helpful!

 

[Biologic]

I'm far from the 1st as well. @Lasse did this well before me, as well as others.

The real benefit of recirculation is longer life for media and damp air. When I didn't recirculate I'd have pH glitches and have to troubleshoot. Was the media exhausted? Not damp enough? Etc.. Once I figured out the water added to the bottom was quickly being used up (which also reduces efficacy). I was constantly opening and adding water to the media container. Some setups even have a container just with water prior to the media chamber. I just went recirculation...no more problems with keeping the air damp with the added benefit of longer media life.

Fortunately living in a humid area where is 91% right now, naturally condensation builds up inside the CO2 scrubber. I realize re scrubbing air scavenges any remaining CO2, though I never saw a difference on my previous skimmer. I suspect it was too small to make a difference.

Also, I noticed with a recirculating CO2 scrubber, there is a vacuum effect, where the skimmer would lose some of the air overtime, and the water replacing it moves the air column up. I’ve seen people complaining about this before, but never mentioned exactly the phenomenon of a vacuum. They think it’s a crazy over foaming skimmer, when I think it’s a skimmer that has too much water in it. It was relieved when I open an air valve to introduce new air into the system. That’s a big reason why I abandoned it, apart from having no affect on my pH.

Your results have me very tempted to upgrade my skimmer. I hate to go HOB with an AIO tank but I suspect it's the only way to get something with enough power. Great post, very helpful!

Find a large skimmer. I know. I hate this JBJ all in one. It’s a bore to work with. Very tiny compartments. Poor design by today’s standards. Growing SPS just find in it, but a pain to work with.

I didn’t want a skimmer at first but simply adding one improved my nutrient control significantly. Now boosting my pH is just the cherry on top. Sitting at 8.2 at 11 PM and my pH stayed at 8.2 until the morning lights came on and took over pH. Hit 8.26 today. 0.06 fluctuation. Amazing. Months I had a 0.35 fluctuating diurnal swing.

I highly suggest Deltec MCE 600 or 601. I got the 220v version and just got a converter for 120v. They are not cheap, but they produce real skimmate. Not typical HOB skimmate “tea”.

 

[Lasse]

For the books - recirculation of the the skimmer air will make the air without oxygen after a while, hence no oxygen either in or out from the system. IMO - the skimmers most important role is as an gas exchanger, this will not happen if it is 100% recirculated. It must be at least 50% new air - IMO. But you will lose some of the skimmers ability to bring in oxygen to the system during night time.

Sincerely Lasse

 

[Biologic]

For the books - recirculation of the the skimmer air will make the air without oxygen after a while, hence no oxygen either in or out from the system. IMO - the skimmers most important role is as an gas exchanger, this will not happen if it is 100% recirculated. It must be at least 50% new air - IMO. But you will lose some of the skimmers ability to bring in oxygen to the system during night time.

Sincerely Lasse

how does one allow 50% air into the system? From what it seems, air took the least path of resistance. By passing the CO2 scrubber. I almost need a solenoid system to periodically turn the recirculating off to allow Oxygen into the system.

 

[arking_mark]

how does one allow 50% air into the system? From what it seems, air took the least path of resistance. By passing the CO2 scrubber. I almost need a solenoid system to periodically turn the recirculating off to allow Oxygen into the system.

I'll share my build.

My CO2 recirculation is built into the top of my skimmer through 2 of the 4 existing holes. So not a sealed recirculation. So my recirculated air is probably mostly recirculated and no vacuum issues. My O2 is always saturated (it's monitored).

 

[Calm Blue Ocean]

Find a large skimmer. I know. I hate this JBJ all in one. It’s a bore to work with. Very tiny compartments. Poor design by today’s standards. Growing SPS just find in it, but a pain to work with.

I didn’t want a skimmer at first but simply adding one improved my nutrient control significantly. Now boosting my pH is just the cherry on top. Sitting at 8.2 at 11 PM and my pH stayed at 8.2 until the morning lights came on and took over pH. Hit 8.26 today. 0.06 fluctuation. Amazing. Months I had a 0.35 fluctuating diurnal swing.

I highly suggest Deltec MCE 600 or 601. I got the 220v version and just got a converter for 120v. They are not cheap, but they produce real skimmate. Not typical HOB skimmate “tea”.

My pH battles have been so similar to yours, lucky to hit 8.0 with the windows open and the bathroom exhaust fan on. Add to that my battle with nutrients and failed carbon dosing due to inadequate skimming, it's hard to not see the writing on the wall. It's time for a real skimmer.

Here's my typical "tea". I don't think it's working.

 

[Biologic]

My pH battles have been so similar to yours, lucky to hit 8.0 with the windows open and the bathroom exhaust fan on. Add to that my battle with nutrients and failed carbon dosing due to inadequate skimming, it's hard to not see the writing on the wall. It's time for a real skimmer.

Here's my typical "tea". I don't think it's working.

oh man I feel your pain. I recognize that skimmer cup. I’ve worked in LFS retail back in 2006 to 2008 and I’ve seen lots of HOB’s in that time. I got out of the hobby until 2020. I’ve seen cheapo skimmers HOB’s and while they are tempting, they always under perform. If there was one other brand besides Deltec, I’d use AquaMaxx’s HOB’s. They look like they would be solid performers.

The issue is there’s not many people running HOB’s, so there’s not much effective equipment choices out there. Unfortunately not many LFS’s and dry good suppliers don’t properly set expectations on how these products perform. They have good margins and that’s the reason why they are sold.

 

[Paston1]

Try a wooden stone that turns on at night when lights are off. Turns whole tank into a skimmer which helps with the gas exchange.

 

[Biologic]

Try a wooden stone that turns on at night when lights are off. Turns whole tank into a skimmer which helps with the gas exchange.

See I don't think that's a good idea. Here's why -- If you run a CO2 test for an hour, aerate a small volume of liquid, test pH before and after aeration, the pH doesn't go up or even goes down, the issue is the CO2 levels in the home. Go outside and run the same test, if the pH rises, then the air outside is less concentrated with CO2 than the inside. More than likely this is the case.

If your skimmer is already properly sized, adding in additional air will likely not make any improvement. HOWEVER, pulling air outside the home, especially if you live in an area with low cars and traffic, in the suburbs, will make a significant improvement.


An update to this post -- a larger oversized skimmer, running air from the outside, with a non-recirculating CO2 scrubber, significantly improved my pH levels. I do not go into the 7's in pH. I stay above 8.15 and peak around 8.30. I replaced the CO2 Scrubbing Media after one month.

 

[Paston1]

See I don't think that's a good idea. Here's why -- If you run a CO2 test for an hour, aerate a small volume of liquid, test pH before and after aeration, the pH doesn't go up or even goes down, the issue is the CO2 levels in the home. Go outside and run the same test, if the pH rises, then the air outside is less concentrated with CO2 than the inside. More than likely this is the case.

If your skimmer is already properly sized, adding in additional air will likely not make any improvement. HOWEVER, pulling air outside the home, especially if you live in an area with low cars and traffic, in the suburbs, will make a significant improvement.


An update to this post -- a larger oversized skimmer, running air from the outside, with a non-recirculating CO2 scrubber, significantly improved my pH levels. I do not go into the 7's in pH. I stay above 8.15 and peak around 8.30. I replaced the CO2 Scrubbing Media after one month.

I use it on my tank, the tsnk is in my bedroom. Me, wife, and dog. Ph drops .1 at night.
Even if the ph doesn’t see a improvement. The bubbles like what your skimmer does, turns the whole tank into a skimmer. Removing items from display and bringing to the sump for proper filtration and removal.
A lot of your sps dealers run the bubblers at night and never tell you. Sadly it’s a secret I found due to thinking about the ocean and waves. Then thinking about the bubbles the ocean has. Then going a local coral dealer and see his on in his tank before he could shut it off.
It’s helping with the gas exchange for the coral which is more important than overall ph wise would argue. Bubble reefing theory. It’s a valid one that WWC uses actually.

 

[Biologic]

I use it on my tank, the tsnk is in my bedroom. Me, wife, and dog. Ph drops .1 at night.
Even if the ph doesn’t see a improvement. The bubbles like what your skimmer does, turns the whole tank into a skimmer. Removing items from display and bringing to the sump for proper filtration and removal.
A lot of your sps dealers run the bubblers at night and never tell you. Sadly it’s a secret I found due to thinking about the ocean and waves. Then thinking about the bubbles the ocean has. Then going a local coral dealer and see his on in his tank before he could shut it off.
It’s helping with the gas exchange for the coral which is more important than overall ph wise would argue. Bubble reefing theory. It’s a valid one that WWC uses actually.

Dang I will definitely try it out. Sounds like you really believe in it. I’ll report back if makes an improvement.

 

[Garf]

Dang I will definitely try it out. Sounds like you really believe in it. I’ll report back if makes an improvement.

I think ive read that supersaturating the actual tank can cause massive fish problems, pop eye, death, etc.

@Jay Hemdal ? Are you around?

 

[Biologic]

I think ive read that supersaturating the actual tank can cause massive fish problems, pop eye, death, etc.

@Jay Hemdal ? Are you around?

for what it’s worth, I am using a skimmer that’s 4x over rated for my tank right now. It’s a Deltec MCE 601 HOB. You can put this on a 120gallon comfortably with a medium bio load.