Big Bubbler for pH?

[JVU]

Hey all. My pH is ok without any messing-with, about 7.8-8.1 (min at 6a, max at 6p, due to the photoperiod and despite refugium on opposite schedule). I had an episode last year with trying out All-For-Reef where my pH bottomed out and was a contributing factor in a pretty bad episode of RTN (in my opinion). Another episode with the Neptune feeder dumping a bunch of food in tanked my pH again and contributed to another RTN extravaganza. I feel like if my pH were higher it would give me more of a buffer. Plus aiming for pH 8.3 and more stability to mimic the reefs seems like a good idea.

I’ve been trying a CO2 scrubber the past few months, and it gets to me about 8.1-8.4, trending down to 7.9-8.2 before I change it out. I bought a lot of the CO2 scrubber media, so I could just keep doing that without much issue.

I was messing around with a CO2/pH calculator (https://www.hamzasreef.com/Contents/Calculators/CO2LevelSalt.php). My home air CO2 is generally pretty good, about 400-600 ppm. In the garage (which I can easily run a tube to) it is more like 400-500 ppm and more consistent. If the tank CO2 was equilibrated with my air CO2, my pH would always be pretty good 24/7, with minimal swings. Ex: alk 8.5 dKH, salinity 35 ppt, temp 78F, CO2 450 ppm = pH 8.3. CO2 600 = pH 8.2.

Randy Holmes Farley also mentioned that in a tank with perfect gas exchange, there would be no cyclical nature to the tank pH, which makes sense and is appealing, regardless of the absolute number.

So this got me thinking about having a massive air bubbler running in the largest spare compartment in the tank setup, the overflow chamber. I have a RSR750, so the chamber is the height of the tank and quite a significant volume of water, with a lid on top to reduce bubble spray.

I was thinking of a big air pump like this 10w model and a large air stone like following-

https://smile.amazon.com/Hygger-Quietest-Aquarium-Adjustable-Powerful/dp/B07YDFVPMS

https://smile.amazon.com/Hygger-Aquarium-Hydroponics-Ultra-High-Dissolved/dp/B07MYQHRT2

Goal would be reducing the lows of the pH cyclical variation and have the pH pegged around 8.2-8.3 with air from the garage, and a more natural approach than other options out there. Anyone have any experience or thoughts?

 

[rdriggett]

I have heard positive reviews about your linked 10W air pump. I plan to get the 5W model myself.

 

[JimWelsh]

Doesn't the water in the overflow generally already experience a fair amount of air exchange as it makes its way down to the sump? It seems as though the big bubbler should be somewhere else where the water is otherwise more still, but of course, salt creep is always a concern when there are lots of bubbles happening.

 

[Qwiv]

You think you will maybe make skimmate? Probably not since it will be skimmed off nonstop. but that could maybe be a better location to use a CO2 scrubber as you don’t need to worry about a collection cup overfilling the intake line. probably Not as efficient, but the safety factor is appealing.

 

[Turkeysammich]

Wouldn’t that just be running a skimmer with out the cup ? That’s a big air pump.
What really moves ph for me is Kalk.

 

[Coral reefer]

Doesn't the water in the overflow generally already experience a fair amount of air exchange as it makes its way down to the sump? It seems as though the big bubbler should be somewhere else where the water is otherwise more still, but of course, salt creep is always a concern when there are lots of bubbles happening.

This was my initial thought as well

 

[Joseph Lee]

I think it would be a great idea. Some thoughts below:
1. Small fine bubble vs bigger bubble. I am not sure which one is better but I feel that bigger bubbles would be better because it creates more turbulence and more agitation on the water surface.
2. You could also consider leaving your cabinet door open or installing a fan inside the sump to blow the room air into the cabinet - I read that most of the cabinets are confined thus there is more co2 inside the cabinet than in the room.
3. Your CO2 scrubber will last longer than before with the addition of a bubbler or/and fan.
4. I am doing something similar (see pics below). It is just experimentation but I feel like it is helping at least a little bit.
O2 is fed from a tiny air pump outside my house.

 

[Da_Neefer]

I wouldn't think the bubbler would give you much of a PH rise considering the skimmer and overflow along with surface agitation from your circulation pumps. I'd be interested to see if you noticed a significant difference after testing it out. I'm currently getting 7.8-8.1ph with a Kalk stirrer and CO2 reactor and have been researching dosing Kalk slurry to acheive a set ph level of 8.3. Need to wrap my head around the math involved and get parts setup to do it. It woul dreplace the Calcium reactor and stirrer altogether. I'd dose Mg separately.

 

[JVU]

Doesn't the water in the overflow generally already experience a fair amount of air exchange as it makes its way down to the sump? It seems as though the big bubbler should be somewhere else where the water is otherwise more still, but of course, salt creep is always a concern when there are lots of bubbles happening.

In my Red Sea Reefer, it is specifically optimized to make no gurgling noises- 1 drain is complete siphon and the other is either no flow or minimal flow along the wall of the drain. There’s a little turbulence from the water coming over the weirs but really minimal. There are no bubbles coming down the overflow pipes into the sump. It’s a tall column of water with only a little air surface on top. I don’t think there’s much gas exchange. And if there where, I wouldn’t have my pH drop so much at night, right? I could see in other system not optimized to be quiet there could be significant gas exchange.

You think you will maybe make skimmate? Probably not since it will be skimmed off nonstop. but that could maybe be a better location to use a CO2 scrubber as you don’t need to worry about a collection cup overfilling the intake line. probably Not as efficient, but the safety factor is appealing.

Yeah, that is a concern. I have an oversized skimmer running 24/7 already and despite tuning it to make relatively wet foam it still doesn’t usually have much of a foam head. My best guess is that it will make some foam but it won’t bother me because I can’t see inside there. I don’t think it’ll cause problems with the overflow pipes due to their design but not sure about that. I guess it would be something to keep an eye on.

Wouldn’t that just be running a skimmer with out the cup ? That’s a big air pump.
What really moves ph for me is Kalk.

Yep. In addition to the skimmer I already have, since the first isn’t doing enough gas exchange apparently. I know kalk would raise pH, but I’ve already got a dosing system I like and feel is safer. Plus I’m interested in flattening the pH curve as much as the absolute value. It is appealing that just having the tank exchange gas more efficiently as opposed to adding more chemicals could address both issues.

I think it would be a great idea. Some thoughts below:
1. Small fine bubble vs bigger bubble. I am not sure which one is better but I feel that bigger bubbles would be better because it creates more turbulence and more agitation on the water surface.
2. You could also consider leaving your cabinet door open or installing a fan inside the sump to blow the room air into the cabinet - I read that most of the cabinets are confined thus there is more co2 inside the cabinet than in the room.
3. Your CO2 scrubber will last longer than before with the addition of a bubbler or/and fan.
4. I am doing something similar (see pics below). It is just experimentation but I feel like it is helping at least a little bit.
O2 is fed from a tiny air pump outside my house.
View attachment 37646View attachment 37647

Thanks. My thought on bubble size is that finer is better since there is more surface area for gas exchange.

I have tried keeping the sump cabinet door open with a fan, but the main effect is cooling the tank very effectively by evaporation. Also I’ve tested the CO2 level in the air in the closed sump and it actually is already pretty close to room air, so not much benefit to be had by further ventilation in my case.

I wouldn't think the bubbler would give you much of a PH rise considering the skimmer and overflow along with surface agitation from your circulation pumps. I'd be interested to see if you noticed a significant difference after testing it out. I'm currently getting 7.8-8.1ph with a Kalk stirrer and CO2 reactor and have been researching dosing Kalk slurry to acheive a set ph level of 8.3. Need to wrap my head around the math involved and get parts setup to do it. It woul dreplace the Calcium reactor and stirrer altogether. I'd dose Mg separately.

I would have agreed with you before I started reading more about the daily swing in pH and playing with the CO2 vs pH calculator. Now, I’m pretty sure that our tanks are deficient in gas exchange, even with skimmers, power heads pointing at the surface, overflow to sump, etc. It seems to be fine for O2, but not for CO2.

 

[Turkeysammich]

@JVU I have a few skimmer pumps if you wanna try them

 

[RandyC]

I have tried air pumps before and though this is unscientific and completely anecdote, I don’t think you’ll see much of a change if you have a tank full of fish and coral with the air pumps. I think you may be underestimating how much co2 is being produced. Don’t forget that coral will be going through respiration at night as well as your fish. And a mature tank full of big coral colonies will produce a significant amount of co2.

I tried briefly on my 6x3’ frag tank in the garage with air pumps. It has a huge surface area and I still wasn’t able to swing the pH with much significance with 2 air pumps and an added skimmer. I think you’d be better off having something that actually used up the co2 in the water. My guess is a big and very well lit (surrounded by light) fuge and a frag tank running opposite cycle of your DT lights will yield better results.

I’m actually trying this in my reefer 250 now. There are actually two light panels on my fuge; one in front and one on the side. The second light panel was turned off for a while, but I turned it back on when I took out the skimmer and added coral frags to the sump. Since doing this, I only see a 0.1 pH swing at night. Before adding the coral in the fuge and turning on the second light panel, my swing was around 0.25-0.3.

 

[JVU]

I have tried air pumps before and though this is unscientific and completely anecdote, I don’t think you’ll see much of a change if you have a tank full of fish and coral with the air pumps. I think you may be underestimating how much co2 is being produced. Don’t forget that coral will be going through respiration at night as well as your fish. And a mature tank full of big coral colonies will produce a significant amount of co2.

I tried briefly on my 6x3’ frag tank in the garage with air pumps. It has a huge surface area and I still wasn’t able to swing the pH with much significance with 2 air pumps and an added skimmer. I think you’d be better off having something that actually used up the co2 in the water. My guess is a big and very well lit (surrounded by light) fuge and a frag tank running opposite cycle of your DT lights will yield better results.

I’m actually trying this in my reefer 250 now. There are actually two light panels on my fuge; one in front and one on the side. The second light panel was turned off for a while, but I turned it back on when the I took out the skimmer and added coral frags to the sump. Since doing this, I only see a 0.1 pH swing at night. Before adding the coral in the fuge and turning on the second light panel, my swing was around 0.25-0.3.

View attachment 37652

I completely agree that the main problem causing lower pH as well as the swing downward at night is I have too much living stuff respirating and producing CO2 all the time, including at night when there isn’t as much photosynthesis to balance it out. I have a refugium that is lit from the top and from the side on the opposite photoperiod already. I think I have the same side panel light actually. I also have a mini frag tank in the sump but I don’t have that lit opposite, so maybe that is something to try.

 

[RandyC]

I completely agree that the main problem causing lower pH as well as the swing downward at night is I have too much living stuff respirating and producing CO2 all the time, including at night when there isn’t as much photosynthesis to balance it out. I have a refugium that is lit from the top and from the side on the opposite photoperiod already. I think I have the same side panel light actually. I also have a mini frag tank in the sump but I don’t have that lit opposite, so maybe that is something to try.

Just an FYI, my fuge is probably bigger than normal. It's a converted 12G Fluval Edge. So it's about a 11 gallon fuge for a 54 gallon display (around 20%). I'm guessing that is probably at play here as well.

 

[Chromis]

What kind of skimmer do you have? I imagine you would do better upgrading your skimmer or leaving the skimmer + CO2 scrubber setup alone. The skimmer creates more water contact time with the bubbles. But interested to see how it goes.

 

[JVU]

What kind of skimmer do you have? I imagine you would do better upgrading your skimmer or leaving the skimmer + CO2 scrubber setup alone. The skimmer creates more water contact time with the bubbles. But interested to see how it goes.

Reef Octopus Regal 200INT 8” with VarioS pump. It’s pretty beefy.

 

[H2OPlayar]

Here is the bigger question for me. Are you not happy with your growth rate? Most reefers I know with 3 plus year tanks actually like a little slower growth for less trimming. My understanding is that if you dose 2 part with soda ash, you get a similar ph boost to that of kalk (I need to dive into the chemistry more to verify this), where as is the sodium bicarbonate that releases the hydrogen (H+) that lowers ph.

My guess is your skimmer does the best job at air exchange as there are many micro bubbles formed in my Reef Octopus skimmer, and that an air stone will just end up making a mess with salt spray. I remember talking to some "more experienced" reefers who saw air stones come into play 15ish years ago, but they didn't stick around.

 

[JVU]

Part of my interest in this is that I think the entire reefing community is likely undervaluing the importance of better gas exchange in our tanks as they grow in and become artificially packed full of animal life. It isn’t really talked about in this way and I suspect there is some low-hanging fruit value here.

For example, the common wisdom often repeated is that if you have a properly sized skimmer, power heads agitating surface water, and a sump, then you should be fine for gas exchange. And that is true if you are focused on avoiding dangerously low O2 levels.

But by definition when we see our pH dip every night we know that gas exchange is not good enough to prevent the buildup of CO2 in our tanks to levels that are much higher than in the surrounding air.

Some numbers- If I use Hamza’s calculator I linked to above and plug in my tank’s numbers of Alk 8.5 dKH, salinity 35 ppt, temp 78F, and I mess with the pH and corresponding CO2 concentrations, I get:

400 ppm CO2 = 8.3 pH (normal outdoor air and ocean values)
600 ppm = 8.15 pH
800 ppm = 8.05 pH
1000 ppm = 8.0 pH (upper limits of recommended indoor CO2)
1200 ppm = 7.9 pH
1500 ppm = 7.8 pH

So when my room air is around 400 ppm and my tank has a pH of 7.8 (which is every morning if I don’t CO2 scrub), then the CO2 level in my tank is almost 4 times higher than it would be if it were in equilibrium with the air, and well above the recommended upper limits for health and safety of people. So over and over I hear reefers say the CO2 in their air is decreasing the pH in their tanks, but actually the CO2 and pH in their tank is much much worse than the CO2 in their air most if not all the time (at least in my situation).

Higher pH in these ranges is associated with faster stony coral growth, but that actually isn’t my interest here since my tank is already overgrown and growth has not been an issue for me. More importantly it is just wanting to maintain a healthy environment for our pets. Not only replicating their natural environment but just generally a good environment since they are our pets and they have no choice but to exist in the water we put them in. Same reason why I don’t keep my Alk at 4 dKH or let my temp swing 75-85F every day or have my salinity at 30 ppt. You could make the same argument about why bother to optimize those parameters if you don’t need to optimize growth, but you’d be missing the point of wanting to provide your reef with healthy parameters with a safety margin for unexpected issues.

 

[rygh]

I run a big airstone in my sump. I use that Hygger pump. Super quiet.
I go on step further, and have the airstone under a powerhead.
It chops the bubbles further, for more surface area.
I also distributes the bubles all around the sump.

 

[rygh]

Opinions;

Low PH, below around 7.8, causes problems with corals.
It does not kill them directly, but if any other parameters are slightly off, you can get RTN quickly.
So perhaps a better way to put it is that is makes them stressed and sensitive.
Above 8.1, and I think there are minimal benefits.

Coral growth is really size based more than anything else.
Larger corals have more area to grow, so increase faster. Exponential growth.
Tiny frags are slow.
Parameters can make a difference also of course, but it is crazy hard to measure, and I think
those are usually dwarfed by the size issue.

 

[Qwiv]

There was a thread on Reefs.org or Article that calculated the air exchange from air stones vs a weir vs just an agitated open top. A weir was much more effective as you are bringing water to the air vs air to the water and it addresses water surface tension more effectively. Kinda started the Coast to Coast overflow thing. I made one on my 6' tank, was very effective. Maybe see if you can add more weirs in your sump with a fan to make sure you have good air down there. You can also add a weir to some overflow box configurations with some DIY.

I can't find the article as the content from that message board is all gone or difficult to find, but I remember experiments were included in it.