pH/alkalinity stability and cooking with natural gas

[gbru316]

As alkalinity consumption has increased in my tank, it's become increasingly difficult to maintain alkalinity stability, even with Trident controlled dosing. I've noticed that whenever we cook with the range (or oven), indoor Co2 increases. This drives pH down which, in turn, decreases alkalinity consumption. I'm not concerned with the pH swing itself, just the resulting impacts on alkalinity consumption as they pertain to dosing. Trident control is very much a reactive process and it seems to be struggling with the fluctuations.

Below are some graphs of data I've collected:

First, Co2 (right side of graph cut-off to maintain date/time consistency across all plots):

Next, alk:

Lastly, pH:

None of this is surprising. Given my understanding (and I could be wrong), it's exactly how I'd expect the tank to react given the increase in dissolved Co2.

Things I've tried:
1. Co2 scrubber
2. Covering tank with plastic wrap (was an experiment)
3. Opening doors when Co2 increases -- effective but not always an option here in Florida.
4. Setting HVAC fan on "low" to disperse Co2.
5. Increasing Trident sampling time to 12 samples/day (every 2 hours). Also set a very wide control range (1.5 dKh) and dosing limit (50%) to accommodate the swings and maintain Trident control.


Options to be explored:
1. Externally venting the range hood. This is going to occur sometime this year as part of a larger remodel
2. Install an ERV. Exploring this option.
3. External skimmer air intake. A possibility once tank is in a more permanent location (see also: aforementioned remodel). Does nothing to reduce Co2 absorption.
4. Kalkwasser. Not sure if this would increase stability or not. I suspect I'd get more of a pH bump than the AF balling method, but that doesn't reduce the Co2 absorption.
5. Fine-tuning powerhead placement to avoid surface agitation.
6. Increasing Trident sampling frequency to every hour. Expensive -- will need to explore ABC reagents to keep cost down.


I know the best path forward would be an ERV but that's not a quick/easy fix. It's certainly not off the table long-term. Is there anything else I'm missing here? Is this even a problem?

 

[Randy Holmes-Farley]

Thanks for posting this! I've not seen data before on what we know is a big source of CO2 in homes. More than people in most homes.

The external hood over the stove will help a lot, and is likely the best bet for stove related CO2, but won't solve the problem completely since if you can smell something cooking across the room, gas is escaping the cooking area.

 

[gbru316]

Thanks for posting this! I've not seen data before on what we know is a big source of CO2 in homes. More than people in most homes.

The external hood over the stove will help a lot, and is likely the best bet for stove related CO2, but won't solve the problem completely since if you can smell something cooking across the room, gas is escaping the cooking area.

No problem! It just so happens that 2 of my interests intersect here: meteorology and reef tanks. So when I saw that the manufacturer of my personal weather station offered a combined IAQ monitor (Co2, PM2.5, PM10) that integrates with their larger ecosystem, I jumped at it. And placed it directly above my aquarium to capture this data.

I have a feeling I'll need to figure out how to auto-start the range hood as remembering to do things like this (turn off the lights, close doors, turn on bathroom vents, etc) are things that certain people struggle with in my house.

 

[ShadowMan]

As alkalinity consumption has increased in my tank, it's become increasingly difficult to maintain alkalinity stability, even with Trident controlled dosing. I've noticed that whenever we cook with the range (or oven), indoor Co2 increases. This drives pH down which, in turn, decreases alkalinity consumption. I'm not concerned with the pH swing itself, just the resulting impacts on alkalinity consumption as they pertain to dosing. Trident control is very much a reactive process and it seems to be struggling with the fluctuations.

Below are some graphs of data I've collected:

First, Co2 (right side of graph cut-off to maintain date/time consistency across all plots):

Next, alk:

Lastly, pH:

None of this is surprising. Given my understanding (and I could be wrong), it's exactly how I'd expect the tank to react given the increase in dissolved Co2.

Things I've tried:
1. Co2 scrubber
2. Covering tank with plastic wrap (was an experiment)
3. Opening doors when Co2 increases -- effective but not always an option here in Florida.
4. Setting HVAC fan on "low" to disperse Co2.
5. Increasing Trident sampling time to 12 samples/day (every 2 hours). Also set a very wide control range (1.5 dKh) and dosing limit (50%) to accommodate the swings and maintain Trident control.


Options to be explored:
1. Externally venting the range hood. This is going to occur sometime this year as part of a larger remodel
2. Install an ERV. Exploring this option.
3. External skimmer air intake. A possibility once tank is in a more permanent location (see also: aforementioned remodel). Does nothing to reduce Co2 absorption.
4. Kalkwasser. Not sure if this would increase stability or not. I suspect I'd get more of a pH bump than the AF balling method, but that doesn't reduce the Co2 absorption.
5. Fine-tuning powerhead placement to avoid surface agitation.
6. Increasing Trident sampling frequency to every hour. Expensive -- will need to explore ABC reagents to keep cost down.


I know the best path forward would be an ERV but that's not a quick/easy fix. It's certainly not off the table long-term. Is there anything else I'm missing here? Is this even a problem?

Well impressed with the CO2 reading... initially wondered how you were able to measure that, I thought I was missing a trick with the APEX , then saw your reply about the meteorology intersection (nice!)

Just out of curiosity, how did you get on with the various 'Things I've tried'?
Also wondering if you had any noticeable improvement with a CO2 scrubber?

 

[gbru316]

Well impressed with the CO2 reading... initially wondered how you were able to measure that, I thought I was missing a trick with the APEX , then saw your reply about the meteorology intersection (nice!)

Just out of curiosity, how did you get on with the various 'Things I've tried'?
Also wondering if you had any noticeable improvement with a CO2 scrubber?

well, I’m still asking about possible solutions I may have missed after trying those things, so not as well as I hoped

the scrubber seems to help bound the lower end a bit but it’s not quite so cut and dry. Its effectiveness is primarily influenced by air rate through the skimmer. I recently switched from a very old reef octopus classic 150int to an aquamaxx dfc-80 and have found that — although the new skimmer seems more effective at skimming it doesn’t drive out co2 as effectively. I suspect that’s due to lower cfm through it but I’m basing that solely on eyeball measurements of the skimmer air volume. I don’t have a good way to quantify airflow rate at this time.

I’m thinking of going back to the Octo as I don’t have a nutrient problem. And with the Octo, my lowest pH reading was typically low-mid 7.9’s where with the Aquamaxx it dips below 7.9.

 

[gbru316]

So far today, dKh high was 9.37, low is currently 8.3.

This is fairly typical after a high co2 event.

It seems like Trident isn’t able to adequately handle the swings — if I had to guess there’s some failsafe logic built in to the calculations to prevent accidents.

I think I’ll reach out to their support to see if there’s any way I can account for this. Because, in theory, that’s the purpose of trident controlled dosing, right?

 

[ShadowMan]

So far today, dKh high was 9.37, low is currently 8.3.

This is fairly typical after a high co2 event.

It seems like Trident isn’t able to adequately handle the swings — if I had to guess there’s some failsafe logic built in to the calculations to prevent accidents.

I think I’ll reach out to their support to see if there’s any way I can account for this. Because, in theory, that’s the purpose of trident controlled dosing, right?

Yes I would definitely reach out to the Neptune support guys, I've found them to be very responsive and helpful when it comes to dialing in the controller and programming.

I only asked about the CO2 scrubber, as I've been battling low pH for a little while too, although mine is due to a closed environment (UK winter doesn't help with keeping windows open) and my tank is in my home office which is in constant use. Struggled to maintain pH of 8, but since installing a CO2 scrubber on my RSK600, it's a constant 8.3... downside to a higher pH is an increase in higher Alk consumption.

To get the skimmer to utilise the scrubber effectively, I had to close one intake and plug the other into the scrubber. (The RSK has 2 inlets)

 

[HankstankXXL750]

Does the drop in pH also coincide with your light schedule. Does it drop when lights are out. I found some help with this by running a refugium light on an opposite schedule. Also my tanks are I. The basement and I have plumbed outside air into the skimmer. This helped me a lot.

 

[gbru316]

Yes I would definitely reach out to the Neptune support guys, I've found them to be very responsive and helpful when it comes to dialing in the controller and programming.

I only asked about the CO2 scrubber, as I've been battling low pH for a little while too, although mine is due to a closed environment (UK winter doesn't help with keeping windows open) and my tank is in my home office which is in constant use. Struggled to maintain pH of 8, but since installing a CO2 scrubber on my RSK600, it's a constant 8.3... downside to a higher pH is an increase in higher Alk consumption.

To get the skimmer to utilise the scrubber effectively, I had to close one intake and plug the other into the scrubber. (The RSK has 2 inlets)

I've never seen a pH of 8.3. 8.2 was about the best I've noticed.

I'm not terribly concerned with the pH level overall or magnitude of swings between day and night, I just want more stability so that one day/night I'm not at 8.15/7.93 and the next at 8.02/7.84. I'd be happy as a clam with 8.1/7.9, 8.05/7.85 or whatever, consistently.

Does the drop in pH also coincide with your light schedule. Does it drop when lights are out. I found some help with this by running a refugium light on an opposite schedule. Also my tanks are I. The basement and I have plumbed outside air into the skimmer. This helped me a lot.

I’m not concerned with the normal day/night variation, I just want to be consistent enough day-to-day that my trident is capable of maintaining alkalinity control.

 

[Hemmdog]

I use this inkbird controller for different uses, it does a great job of keeping co2 levels in check for the price.


Maybe you could set the plug’s on setting to an exhaust fan of some sort or to trigger your fan to disperse the air in the room.

 

[gbru316]

I use this inkbird controller for different uses, it does a great job of keeping co2 levels in check for the price.


Maybe you could set the plug’s on setting to an exhaust fan of some sort or to trigger your fan to disperse the air in the room.

Oh man, thanks for this.

I’ll have to tie it in to the range/oven exhaust fan once we finally have one that vents externally.

 

[YOYOYOReefer]

I adjust my bubble size a bit smaller and push more air into my beckett skimmer in the winter, and have it pulling air from outside.. downside is the heaters have to work a bit more,

 

[HighlandReef]

In general, my house suffers from excess co2, especially in winter. A lot harder to open windows in winter.
Only way I was able to get my PH up was by running skimmer air intake hose to suck in outside air. PH hovers around 8.2 now.
If I don’t use outside air, my PH drops to 7.9.
Outside air made a huge difference on my system.

 

[gbru316]

In general, my house suffers from excess co2, especially in winter. A lot harder to open windows in winter.
Only way I was able to get my PH up was by running skimmer air intake hose to suck in outside air. PH hovers around 8.2 now.
If I don’t use outside air, my PH drops to 7.9.
Outside air made a huge difference on my system.

That makes perfect sense. That's not really the issue I'm trying to solve though.

I'm specifically trying to solve a periodic transient event that I've linked to cooking (via correlating indoor Co2 concentration data with pH and alkalinity data) that seems to throw Trident controlled dosing off the rails.

 

[Randy Holmes-Farley]

That makes perfect sense. That's not really the issue I'm trying to solve though.

I'm specifically trying to solve a periodic transient event that I've linked to cooking (via correlating indoor Co2 concentration data with pH and alkalinity data) that seems to throw Trident controlled dosing off the rails.

If the Trident is dosing based on alk measurement, how is it changing? The pH will be impacted, altering alk demand, but the alk should be steady as the dosing changes to match it..

 

[gbru316]

If the Trident is dosing based on alk measurement, how is it changing? The pH will be impacted, altering alk demand, but the alk should be steady as the dosing changes to match it..

It seems to fail to account for the decrease in alk consumption quickly enough. Almost like some sort of averaging across several measurement points is used to determine dose.

 

[Randy Holmes-Farley]

It seems to fail to account for the decrease in alk consumption quickly enough. Almost like some sort of averaging across several measurement points is used to determine dose.

OK, i have no idea if there's an averaging mechanism or not.

 

[gbru316]

OK, i have no idea if there's an averaging mechanism or not.

Nor do I, but the argument could be made for one in order to prevent overdosing due to an erroneous measurement.

 

[Randy Holmes-Farley]

Nor do I, but the argument could be made for one in order to prevent overdosing due to an erroneous measurement.

Yes, that's true. If so, it also throws into doubt the interpretations folks make about the time of day of alk consumption.

 

[gbru316]

I've decided I need to be a bit more empirical about this -- the role that ambient CO2 plays in pH and alkalinity consumption. And it'd be nice to have a solid data package to share with Neptune if/when I engage them if I'm unable to otherwise figure this out.

Since I log all the Apex sensor/measurement data in an influxDB database and plot using Grafana, it's trivial to extract daily min/max/mean for alk and pH, and Apex shows daily alkalinity dose with the click of a button. CO2 parameter extraction requires a bit more work but nothing difficult -- export daily data, convert from string to number, and find max/min/mean via excel function.

So I've started a spreadsheet logging daily pH, alk, and CO2 min/max/mean along with daily alkalinity dose. I'm curious to see what the data shows once it's all combined and plotted.